Antibiotics (Properties, Application, Interactions) - M.P. Cherenko 1999

General Oncology

CONCEPT OF TUMORS, THEIR SPREAD AND HISTORY OF The Development of THE DOCTRINE

A tumor, neoplasm, or neoplasia is a pathological, uncontrolled proliferation of Cells in any Tissues of the body. It is observed in all Representatives of the animal kingdom—from insects to humans, and even in plants. Tumors develop in the majority of vertebrate animals.

It is currently impossible to give a precise definition of a tumor, as we do not know the underlying, direct causes of the Transformation of a normal Cell into a tumor cell. Therefore, a tumor is usually defined as a cell proliferation accompanied by characteristic features. Accordingly, a tumor can be defined as a pathological reactive cell proliferation characterized by incomplete growth, autonomy (independence from The regulatory mechanisms of the body's influence), morphological and biochemical atypia, and complete functional incompetence. This definition reflects, firstly, the peculiarity of tumor cell growth: it is not physiological, compensatory, or adaptive in nature. Secondly, unlike physiological growth (regenerative or reparative, which continues up to certain limits and ceases after the replacement of lost cells or the filling of a tissue defect, i.e., regulated by the body), tumor growth—although it varies in pace, being either rapid or very slow—never ends, continues until the end of the Organism's life, and is practically unregulated by it.

Tumor cells possess varying degrees of differentiation—from high, when they differ little from analogous cells of healthy tissues and even produce normal secretions (e.g., parathyroid hormone, melanin, ACTH, Insulin), to very low, when it is difficult to determine to which tissue the tumor cells belong, as they bear no resemblance to the primary cells. However, all tumors have a lower Organization compared to normal tissues, meaning they are atypical in both Structure and function. True tumors must be distinguished from pseudo-tumors, which are enlargements of tissue areas due to edema, hematomas, retention cysts, cell HYPERTROPHY AND HYPERPLASIA, etc.

The branch of medicine that studies the origin, spread, Treatment, and Prevention of tumors is called oncology (from *onkos* — tumor, *logos* — science).

Clinically, a distinction is made between benign and malignant tumors. The latter are associated with a threat to human life regardless of the tumor's Location and origin. Benign tumors can also pose a threat to human life in certain locations (e.g., the cranial cavity, intestines) due to the mechanical impact they exert on the Organs from which they grow, or on neighboring organs and structures.

Benign tumors can be detected in almost every person, but statistics for them are absent because they are not registered. In most countries of the world, exclusively malignant tumors are registered, the prevalence of which in industrialized countries ranges from 200 to 400 per 100,000 population. Therefore, when oncological diseases are discussed, they practically refer to malignant tumors, which are called by the general term "Cancer" or "carcinoma", although in a strictly scientific sense, cancer refers to malignant tumors originating from the epithelium of any organ (mucous membranes of The Stomach, intestines, Bronchi, epithelium of exocrine and Endocrine glands, etc.). A malignant tumor originating from mesenchymal tissues—Connective Tissue, Muscles, bones, etc.—is called a Sarcoma (from *sarkos* — muscles).

To denote a tumor (both benign and malignant), the general term "tumor" (Latin *tumor* — Swelling) is widely used.

The search for ways to combat tumor diseases is ongoing. Scientists are seeking Answers TO QUESTIONS that interest all of humanity: What is the underlying cause of cancer? What contributes to the development of malignant neoplasms? Are there populations that do not get cancer? Unfortunately, there is only a gradation based on the quantitative ratios of a particular type of cancer. In some countries, Skin cancer is more common; in others, Oral Cavity cancer; and in still others, stomach cancer. To some extent, this is explained by people's living conditions and lifestyles, their customs and habits. The cities of England, for example, are oversaturated with smog, resulting in the highest prevalence of Lung Cancer there. Africa is characterized by primary Liver Cancer as a consequence of consuming delicacy flatbreads covered in mold, which contains a large amount of carcinogenic substances, etc.

The history of The Study of malignant tumors goes back centuries. The first reports of cancer are found in the ancient "Edwin Smith Papyrus" (2500 BC). The remains of ancient Egyptians who lived 2700 BC show evidence of malignant tumors.

Materials on the study of cancer as a disease can be found in ancient manuscripts, which discuss the problems of tumor Classification and the causes of their occurrence.

By the 12th century, cancer was already known in China, where it received the name "ai", which is still preserved in China today.

The ancient Hindus were the first to divide tumors into benign and malignant. They also pointed out that tumors should be removed.

The credit for introducing The concepts of "cancer" and "sarcoma" into medical practice belongs to Hippocrates and Avicenna. These terms have survived for many centuries. "Cancer" and "carcinoma" are different names for the same concept. Today, over a hundred diseases are grouped under the general name "cancer".

Why is METABOLISM/2.html">THE CONCEPT OF malignant tumors associated with the image of a cancer or a crab?

In ancient times, when the Cytology/cytology/16.html">Early stages of malignant tumors could not yet be recognized and there was no knowledge of how to treat them, many patients sought medical help only in the late Stages of the disease. Deeply seated tumors were inaccessible to the physician's eye at that time, and surgeries were not performed. Doctors were only able to observe external, neglected tumors. For example, breast cancer appears as a large, dense node of a dark red or crimson color protruding above the skin surface, with strands extending from its sides in the form of tentacles or paws. By its color and contours, the tumor resembles a crab or a crayfish.

The foundation for the Development of the doctrine of tumors was laid in the works of Celsus, Galen, Morgagni, and Paracelsus.

Descriptions of the course of malignant tumors can be found in ancient sources discovered on Rus' territory. For instance, the Hypatian Codex describes the clinical picture of lower lip cancer in Prince Volodymyr (Vasylkovych) of Halych.

In Russia, in December 1903, the first institute for the treatment of patients with tumors was opened at Moscow University (today it is the Moscow Research Institute of Oncology).

In the 19th century, A number of important discoveries and inventions were made in biology: the improvement of the Microscope, the substantiation of Cell Theory by the German scientist Theodor Schwann,

the invention of the microtome, etc. All this made it possible to study the microscopic structure of tumors, accumulate a wealth of facts, and make the first scientific generalizations. By the mid-20th century, the Main Features of malignant tumors were already known: autonomy and invasiveness of growth, its uncontrollability, and The ability to metastasize.

All these achievements served as an impetus for the further study of The problem of malignant tumors. These issues began to be addressed not only by clinicians but also by theoreticians: biochemists, pathophysiologists, pathologists, histologists, pharmacologists, and others.

The efforts of scientists from many countries in combating cancer have demonstrated that resolving this problem requires international cooperation. Consequently, in 1933, the International Union Against Cancer was organized, uniting scientists from 70 countries around the world. The First International Cancer Congress took place in the same year, 1933, in Madrid. Subsequent congresses were held every 3–4 years. Over recent decades, scientists have achieved significant successes in the fields of nuclear physics, electronics, space exploration, molecular biology, and many other sciences. It can be expected that experimental oncology, building upon these achievements, will take a decisive step in unraveling the "mystery of cancer". Then clinical oncology will also acquire fundamentally new and effective Methods for both the prevention and treatment of this disease.

Cancer is sometimes called the disease of the century. There is reason to hope that this title will be justified not only by the fact that the number of cancer patients has increased in our century, but perhaps also by the fact that as early as the 20th century, we will come close to conquering this disease.

Etiology AND Pathogenesis OF TUMORS

There is a common misconception that the causes of cancer remain entirely unknown to us. This is no longer true in light of modern oncology. While we may not yet fully understand the primary triggers of cancer, we are well aware of numerous factors that facilitate the transformation of a normal cell into a cancerous one.

Today, a number of theories attempt to explain the development of malignant tumors, yet none of them fully resolve the problem. Scientists believe there is no single specific agent, substance, or organism in our environment that inherently triggers malignant growth. Instead, a complex combination of factors plays a decisive role in the onset and progression of various tumors.

Over a century ago, in 1887, the German pathologist Julius Cohnheim proposed the embryonic rest theory. He explained The Emergence of malignant growth by suggesting that during early embryonic development, certain areas of the embryo produce more cells than necessary for tissue formation. These surplus cells persist as dormant rests. While Cohnheim ruled out the direct hereditary transmission of tumors, he noted that some individuals possess a predisposition to develop them. Some people with this predisposition live to old age and die from entirely unrelated causes, whereas in others, these excess cells transform into malignancies due to yet unknown triggers.

Indeed, Cohnheim's theory can account for THE ORIGIN OF certain benign and malignant tumors, such as atypical breast cancer. However, it fails to explain tumors induced by chemical and physical carcinogens, or The Role of occupational and environmental factors in carcinogenesis.

Clinicians have long observed that malignant tumors frequently develop in areas of chronic tissue irritation caused by external factors. This led Rudolf Virchow to propose his irritation theory of malignant growth in 1863. He based this Conclusion on observations of patients who died from gastrointestinal malignancies, noting that tumors were more likely to form at physiological strictures or junctions between organs (such as the stomach and Esophagus)—areas subjected to frequent trauma. According to Virchow, such irritation could be mechanical, chemical, radiological, or physical in nature.

While emphasizing The Importance of chronic irritation in the genesis of malignant growth, Virchow did not dismiss the role of heredity, the general physiological state of the organism, The Nervous system, or Nutrition.

Virchow’s theory should be viewed as a component of the polyetiological concept, as it cannot account for The Diversity of morphological forms, histological structures, and metastatic potential.

A major drawback of this theory is its failure to identify what actually sparks The process of malignant transformation.

The polyetiological theory of tumor development was formulated by Nikolay Petrov. He emphasized that internal and external causes should not be pitted against one another, as this would contradict the fundamental dialectical law of universal connection and interdependence of phenomena in nature. Regarding the Causes of tumor growth, the role of a multifactorial complex becomes evident. The transformation of a normal cell into a tumor cell may be triggered by disruptions in intracellular and systemic metabolism caused by endogenous and exogenous factors, viral action, hormonal imbalances, or a combination of these causes.

Petrov's polyetiological theory attributes malignant tumor development not to a single cause, but to various physical, chemical, and biological factors that affect the body and induce a proliferative reaction in tissues. When combined with simultaneous Impairment of the nervous, endocrine, and other systems, metabolic shifts occur within tissues, organs, and the body as a whole, which can ultimately drive tumor growth.

In 1775, the English surgeon Percivall Pott observed that chimney sweeps frequently developed scrotal cancer. This was attributed to the chronic embedding of soot into the skin of the Scrotum, as the sweeps climbed into flues wearing little or no clothing.

In 1915, Japanese scientists Katsusaburo Yamagiwa and Koichi Ichikawa successfully induced malignant tumor growth on the ears of rabbits by systematically applying coal tar. It was later established that the causative agent was benzopyrene (BP), a polycyclic aromatic hydrocarbon (PAH). These studies laid the foundation for the modern science of chemical carcinogenesis.

The transformation of a healthy cell into a cancerous one forms the core of the study of carcinogenesis. Many scientists attribute the onset of malignant tumors to environmental factors of physical, chemical, and biological origin, known as carcinogens. They are conventionally divided into cancer initiators and promoters: the former are essential, while the latter are conditional, acting at different phases of cellular malignant transformation.

As early as 1964, a special WHO commission established that nearly 80% of human cancers are caused by chemical carcinogens. These substances are present in urban ambient air, combustion products, tobacco smoke, smoked meats, and certain fruits and vegetables.

Today, over 2,000 chemical substances are known to induce malignant growth upon chronic exposure. These include nitrogen compounds, arsenic, asbestos, phenol, all herbicides and insecticides, synthetic mineral fertilizers, certain medications (such as phenacetin, phenobarbital, immunosuppressants, and chemotherapeutic agents), and others. Many carcinogenic substances are generated during the combustion of oil, gasoline, and coal, entering the atmosphere and subsequently the Lungs, digestive tract, and skin.

In addition to exogenous chemical carcinogens, there are endogenous ones that form naturally within the bodies of humans and animals during metabolic processes.

Alongside chemical carcinogens, physical ones also exist. They may be natural (ultraviolet radiation, cosmic rays including gamma rays, and neutrons) or incorporated (radionuclides, carbon, potassium, radon).

With scientific and technological progress, the Abundance of radionuclides emitting alpha, beta, and gamma radiation has increased in nature. The environmental radiation Background has deteriorated due to the Chornobyl Nuclear Power Plant accident, nuclear submarine and vessel accidents, and the negligent storage of spent nuclear waste.

Physical carcinogens also include extreme temperatures and physical trauma. For instance, esophageal cancer is more prevalent among individuals who habitually consume very hot foods.

The role of trauma—both acute and chronic—in the development of malignant tumors is indisputable. It plays a particularly significant role in the pathogenesis of osteosarcoma. Furthermore, cancerous tumors can arise on the background of trophic ulcers, Burns, frostbite, and bone fractures, among other injuries.

Biological carcinogens include certain parasites, such as schistosomes (associated with Urinary Tract and Bile duct cancers), and metabolic products of the fungus *Aspergillus flavus* (associated with hepatocellular carcinoma).

Chemical carcinogens are the most widespread in nature, and their variety continues to grow each year.

Susceptibility to carcinogens varies among individuals, depending on sex, age, the state of the nervous system, and living conditions. The time elapsed between The entry of a carcinogen into the body and the appearance of the first signs of tumor growth is known as the latent (or incubation) period. This duration largely depends on the Chemical Structure of the carcinogen, as well as the age of the human or animal. Generally, the longer the lifespan of the organism, the longer the latent period; in humans, it typically spans 15 to 20 years.

Carcinogens can induce malignant growth either directly at the site of exposure or at a distance from it.

The precise MECHANISM OF ACTION of carcinogens remains elusive today. Scientists still lack a definitive answer as to why a normal cell transforms into a malignant one under their influence. It is currently hypothesized that carcinogens bind to cellular Proteins and disrupt metabolism, specifically damaging The structure of DNA and RNA.

Proponents of the Hormonal theory of malignant tumor development proceed from the premise that all Hormones, regardless of their chemical structure, share one common property: they stimulate proliferative processes in all tissues. The authors believe that the onset of cancer is rooted in endocrinopathy.

Experimental and clinical observations indicate that estrogens play a crucial role in the development of malignant tumors. Androgens also exhibit a pronounced carcinogenic effect with prolonged use.

Thus, hormones, much like carcinogens, act on The Cell either directly or through the organism, directly affecting its genetic apparatus or cell membranes. Hormones diminish the body's protective and adaptive responses by suppressing antitumor Immunity and the connective tissue system, thereby creating favorable conditions for the development of malignant tumors.

The viral-genetic theory of tumor origin. The role of Viruses in the development of malignant tumors in animals was confirmed by the research of P. Rous. In 1911, he was the first to transplant chicken sarcoma after injecting a filtrate that did not contain tumor cells. These experiments were later replicated by other authors, confirming the presence of a malignant-inducing agent in the cell-free filtrate of chicken sarcoma, known as the Rous sarcoma virus. Similar studies involving other tumors were subsequently conducted in experiments on rabbits and mice (rabbit papilloma, mouse breast cancer).

The viral theory of human malignant tumors was developed by L. Zilber (1945). In 1966, shortly before his death, he completed work on his final monograph, "The Viral-Genetic Theory of Tumor Origin." Over the course of 20 years, the hypothesis evolved into a fully-fledged theory. The core of the malignant transformation of a normal cell lies in the integration of an oncovirus with the cell's genome. This term refers to the joining of viral DNA with one or more segments of the chromosomal DNA of normal cells.

The exact mechanism of malignant cell transformation remains unknown. Initially, changes occur in the genetic protein under The Influence of a specific carcinogen (or virus). Amino acid sequences identical to those involved in viral transformation have been found in The Genome of normal cells. In an activated state, these "oncogenes" can trigger transformation, marking the first step in tumor formation. Transformations occur constantly, but thanks to immune surveillance or simple "sloughing"—the loss of surface cells—mutant cells are destroyed before they can multiply. Defense mechanisms must be compromised in order for neoplastic cells to easily replicate themselves within the host tissues and proliferate. It is also possible that for a tumor to form, native cells must undergo alterations that enable them to multiply in a mutant form.

Furthermore, the host must be exposed to environmental agents that promote tumor growth. An example of this is hormone-dependent cancers, which require shifts in the hormonal balance produced by endocrine glands to maintain continuous growth.

While viruses are abundant in nature (around 600 species), only about 1/4 of them possess oncogenic properties. Both viral DNA and RNA are capable of carrying malignant information.

The outcome of the interaction between an oncovirus and a cell depends entirely on the latter. If the cell is resistant to viruses, no changes occur within it.

A virus remains non-oncogenic until its genome is incorporated into the cellular genome.

While the role of viruses in animal tumorigenesis has been proven, In humans the viral etiology of tumors has been established for only a small number of benign neoplasms, such as certain types of skin Papillomas and warts.

The genetic theory of tumor origin has gained increasingly widespread support in recent years. Its proponents suggest that the common link in oncogenesis of any etiology is the activation of the cell's own latent potential oncogenes. The appearance of congenital neoplasms is associated with them; however, hereditary predisposition has been proven for only 50% of tumors. Dominantly inherited tumors include basal cell carcinoma, acoustic neuroma, osteochondroma, lipomatosis, cervical polyposis, and neurofibromatosis. Recessively inherited tumors include plasmacytoma and embryonal nephroma.

Oncogenes are often inherited alongside other genes. For instance, stomach cancer is more frequently observed in individuals with Blood group II (A).

Nevertheless, despite all the aforementioned findings, the heritability of oncological diseases in humans has not been definitively proven. Current scientific efforts are focused on identifying markers of a hereditary predisposition to malignancies, thereby classifying such individuals into risk groups for cancer prevention. Researchers believe that close relatives of cancer patients should be designated as a high-risk group and undergo regular systematic examinations.

When examining the etiopathogenesis of tumors, it must be emphasized that this disease does not develop overnight. The foundation for cancer development is laid over months, years, or even decades. The background conditions from which cancer may arise are referred to as precancerous processes, or precancer.

Precancerous conditions have become the subject of intensive study over the past 30–40 years.

Clinical observations demonstrate that malignant tumors frequently develop on The basis of chronic diseases or benign neoplasms. Conditions that invariably transform into cancer are termed obligate precancers, whereas conditions against which a malignant process may develop are termed facultative. Today, the term "precancer" is recognized by both pathomorphologists and clinicians. Obligate precancers include hereditary polyposis of the Large Intestine, xeroderma pigmentosum of the skin, adenomatous gastric polyps, certain types of mastopathy, and benign tumors (though the latter do not always undergo malignant transformation). Facultative precancers comprise various chronic inflammatory processes and proliferation foci, burn scars, poorly healing ulcers, Leukoplakia, cervical erosion, and polyps.

Precancer progresses into cancer As a result of tumor progression—that is, the continuous alteration of tumor cell properties toward increased malignancy. Precancer typically lacks one or more features characteristic of fully developed cancer, and identifying these features is not always straightforward. In some cases, the transition from a precancerous process to cancer is protracted, while in others it occurs very rapidly.

The process of transforming a normal cell into a tumor cell proceeds in a specific sequence. Carcinogenic Factors acting directly on tissue lead to metabolic and Cell Division disorders. A new generation of cells emerges, upon which these factors continue to act, accompanied by further metabolic shifts toward malignancy. Interacting with one another, all these factors establish the groundwork for cancer development.

Epidemiology OF TUMORS

Epidemiology examines the prevalence of malignant tumors across various population groups, The impact of climate, habits, customs, and traditions on these rates, as well as cancer mortality statistics among different demographics. Epidemiologists determine both the overall incidence of cancer within a given population and the incidence of specific tumor types (breast, stomach, lung, Colorectal Cancer, etc.).

It has been established that certain geographic zones in the world exhibit maximum cancer morbidity rates, with incidence linked to climate and exposure to external harmful factors.

A thorough knowledge of cancer epidemiology is of paramount importance as it provides the basis for developing comprehensive preventive measures.

Studies have shown that cancer incidence varied across the republics of the former USSR. According to N. Napalkov and co-authors (1982), cancer incidence in the RSFSR in 1980 was 321.3 per 100,000 population, in the Ukrainian SSR — 238.6, in the Byelorussian SSR — 190.4, in Estonia — 271.4, in Uzbekistan — 73.6, and in Tajikistan — 71.6.

According to data from B. Bilynsky and co-authors, between 1968 and 1982 there was an overall upward trend in the incidence of malignant tumors among the population of Ukraine. Among men, lung cancer ranks first, while among women, breast cancer is most prevalent. The incidence of stomach cancer has remained relatively stable among men, whereas it has noticeably decreased among women. Cervical cancer incidence has seen a particularly sharp decline.

Epidemiological studies of malignant tumors in various locations have brought us closer to the possibility of influencing the incidence rates of specific forms of cancer and achieving their reduction.

TUMOR CLASSIFICATION

A tumor cell population is not anarchic. This tissue has its own pathologically altered innervation, Blood Circulation, and lymphatic drainage. Tumor tissue consists of parenchyma and connective tissue elements. In some tumors, connective tissue elements predominate (scirrhus), while in others, parenchymal cells do so (medullary carcinoma).

The malignancy of a tumor is determined by the degree of cellular differentiation and organization, and its growth depends on The Nature of the carcinogenic factor, the condition of the body, constitution, hormonal balance, nutrition, and external and internal stimuli that alter the internal environment. Low cellular differentiation promotes their proliferation, causing them to become even more immature over time.

Malignant tumor cells proliferate infinitely. They evade regulatory mechanisms. Only certain tumors developing from endocrine glands are subject to Hormonal Influences to some extent.

In tumor tissue, the size and shape of cells change significantly. The proteins of a tumor cell differ from those of healthy cells, but the proteins of different tumors are similar to one another.

Several classifications of tumors exist.

1. Morphological and histological classification: a) a tumor is named after the tissue from which it develops (epithelioma, myoma, angioma, osteoma, etc.); b) According to the number of tissues comprising the tumor: simple tumors, consisting of a single tissue (myoma, chondroma, osteoma, etc.); mixed tumors, consisting of two or more tissues (fibromyoma, osteochondroma, fibrolipoma, etc.); complex tumors, which replicate the structure of an organ (hypernephroma, chondroepithelioma, etc.); mature and immature forms are distinguished based on The Nature and STRUCTURE OF THE tumor cells.

2. Clinical classification. According to this classification, all tumors are divided into benign and malignant. Each of them has its own specific features.

A benign tumor (tumor benignum) is characterized by slow, uniform, expansive growth, during which neighboring tissues are pushed aside. A benign tumor has a capsule; it is not complicated by ulceration, does not alter the skin, and does not cause enlargement of regional Lymph Nodes. The General condition of the patients is not impaired. Only when the tumor is large and compresses adjacent organs may certain local and general manifestations occur (tumors can compress the Pharynx, Larynx, esophagus, or Brain tissue). After the removal of a benign tumor, its growth does not resume at that site (no recurrence). Benign tumor cells do not spread to distant PARTS OF THE body (they do not metastasize). They are mature and, in their structure, differ little from the parent tissue.

A malignant tumor (tumor malignum) is characterized by atypical growth, pronounced polymorphism, a high number of mitoses, cellular immaturity, and aggressiveness toward adjacent tissues. It exhibits infiltrative growth, whereby the tumor tissue penetrates between healthy cells, compressing and destroying them. Over time, it undergoes necrosis with ulceration, leading to the enlargement of regional and distant lymph nodes. Exhaustion (cachexia) gradually develops, and blood composition is disrupted (anemia). After tumor removal, its growth may resume at that site (recurrence). Malignant tumors are characterized by metastasis (the spread of tumor cells to distant parts of the body) via lymphatic, hematogenous, contact, or implantation pathways. In early stages, metastasis occurs to regional lymph nodes. At one time, this was considered The First stage of malignant tumor spread, and it was believed that if the tumor and regional lymph nodes were removed at this point, the patient would recover. Current views on this are different. It is now believed that even at a very early stage of growth, tumor cells enter the lymphatic and Blood Vessels, which disseminate them throughout the body, forming micrometastases. Lymph node involvement does not indicate a specific stage of the disease; it merely indicates that the spread has already progressed significantly.

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Fig. 109. Traditional (a) and modern (b) concepts of the "explosive" spread of breast cancer (Forest, Carter, MacLeod)

It was precisely this Concept of the "explosive" spread of cancer (Fig. 109) that served as the basis for reassessing the role of local treatment and determining the necessity of systemic treatment and long-term monitoring.

The Mechanism of tumor cell dissemination is not yet fully understood. Malignant cells secrete numerous factors that can determine their biological behavior and promote tumor growth and metastasis. For instance, the "angiogenesis factor" stimulates the growth of surrounding capillaries, Proteolytic Enzymes "digest" adjacent fibrous tissue, etc.

During histological examination of malignant tumors, cellular differentiation—namely tissue anaplasia, or The formation of less differentiated tissue—can be observed. Cells lose their function, which no longer meets the body's requirements, meaning functional anaplasia develops.

A distinctive feature of a benign tumor is its ability to undergo malignant transformation. Some benign tumors very rarely turn malignant (angioma, osteoma), while others, conversely, frequently undergo malignant degeneration (papilloma, certain types of nevus). This depends on the Nature of the cells constituting the benign tumor, as well as its location (for example, an osteoma of the cranial bones almost never transforms into an osteosarcoma, whereas an identical osteoma of the Tibia frequently undergoes malignant transformation due to constant trauma).

General Principles of CLINICAL PRACTICE AND Diagnosis OF TUMORS

It is believed that in oncology, a timely diagnosis determines the patient's fate. Diagnosing a tumor (especially a malignant one) in the late stages of the disease is not very difficult, but curing the patient is rarely possible. Hence, the conclusion arises regarding the necessity of early tumor diagnosis. It should be noted that this is often not all that difficult, provided the physician possesses so-called oncological alertness. What does this entail? B. Peterson characterizes it as follows: 1) knowledge of the symptoms of malignant tumors in early stages; 2) knowledge of precancerous conditions and their treatment; 3) knowledge of the organization principles of oncological care; 4) thorough examination of every patient consulting any type of specialist regarding a potential oncological disease; 5) suspicion of an oncological disease in diagnostically difficult cases.

Recognizing tumors at an early stage requires the application of all available diagnostic measures. A well-known surgical oncologist was once asked whether there is any specific reaction to cancer. He replied that there are, in fact, two. The first is the patient's correct reaction to the onset of the disease's manifestations, prompting them to seek medical help in a timely manner, and the second is the physician's correct reaction to the patient's Complaints. These two reactions often ensure a timely diagnosis.

Thus, the first reaction is the patient's reaction (seeking medical attention in a timely manner). Why does this often fail to happen? The ancient Greeks said that pain is the watchdog of disease. In the early stages of an oncological disease, pain may not bother the patient at all, and consequently, the patient does not consult a physician.

The second reaction is the physician's reaction to the patient's manifestations of the disease. What characterizes the Clinical presentation of a tumor, and on the basis of what data can a physician, if not establish a precise diagnosis, at least suspect the possibility of malignant growth? The clinical picture of a tumor is determined by its nature (benign, malignant), size, location, and the complex of functional Disorders of the organ from which it grows (Cancer of the lip, oral cavity, stomach, etc.). The clinical picture of each tumor has its own specific features. Nevertheless, tumors also share general manifestations. Above all, an insidious onset is characteristic of all tumors. Preclinical (latent) and clinical stages of tumor development are distinguished. The preclinical period varies for different tumor locations. Experimental studies indicate that 3/4 of a tumor's lifespan falls within the preclinical, or latent, stage.

Understandably, diagnosing a tumor during the preclinical period is very difficult, if not impossible. Specialized preventive examinations of high-risk population groups can play a certain role in this regard.

Diagnosis is also difficult in the early clinical period. Here, it must be remembered that benign tumors do not cause the patient severe distress. Only when they significantly increase in size do they compress adjacent organs and tissues, causing impairment in the shape or function of a given organ.

In the case of superficially located, so-called visual tumors (mucous membrane of the Lips, oral cavity, breast), the diagnosis is established more quickly (provided there is oncological alertness), because patients seek help themselves. In the case of internal organ tumors, patients usually visit a doctor only when the function of a particular organ is impaired. However, during this period, especially in the case of malignant tumors, other manifestations appear as well: weakness, loss of appetite, decreased work capacity, and unexplained weight loss.

During Anamnesis collection, it is essential to establish the disease duration, the presence of occupational or environmental hazards, chronic diseases, congenital tumors, pathological discharges, and genetic predisposition (a family history of cancer).

During the physical examination, attention should be paid to the patient's general condition, skin color (pallor, jaundice), subcutaneous tissue status, gait, and any potential protrusions or other pathological changes in various parts of the body (e.g., breast enlargement in the presence of a tumor; intestinal peristalsis visible on the anterior abdominal wall when a tumor causes bowel obstruction).

Objective Examination of the patient is of critical importance for diagnosis. In benign growth, the patient's general condition remains virtually unchanged, whereas in malignant cases, patients appear exhausted, cachectic, lethargic, and depressed.

Direct examination of the tumor (when superficially located) significantly AIDS in diagnosis. The shape, size, surface, consistency, and mobility of the tumor, as well as the enlargement of regional and distant lymph nodes, are all of diagnostic value.

During the objective examination, attention must be paid to the condition of adjacent and distant organs (to determine the extent of tumor spread and select the appropriate treatment method).

Every individual, particularly those over the age of 40, who consults a physician for any health issue should undergo a mandatory comprehensive examination, including inspection of the skin and rectum, and in women, a breast examination and pelvic examination.

A meticulously gathered anamnesis and objective examination frequently make it possible to establish an accurate diagnosis without The Use of supplementary methods.

Supplementary diagnostic methods include laboratory, endoscopic, radiological, and radionuclide investigations, among others.

To date, no specific laboratory test for cancer has been identified. Current Laboratory tests are predominantly general in nature and depend on the tumor's localization. For instance, sputum analysis is performed for lung cancer, gastric juice analysis for stomach cancer, stool examination for intestinal tumors, and urinalysis for tumors of the urinary tract, etc.

Laboratory testing holds greater significance in the postoperative period to detect residual cancer cells. Such markers include elevated levels of acid phosphatase following the removal of prostate cancer, human chorionic gonadotropin after chorionic epithelioma removal, carcinoembryonic antigen (CEA) after colorectal cancer removal, and alpha-fetoprotein (AFP) after liver cancer surgery. CEA and AFP are so-called oncofetal Antigens, which are secreted by fetal tissues and certain tumors. These markers are less helpful in early disease diagnosis and more indicative of recurrence progression.

Certain laboratory findings in patients with suspected cancer should also raise suspicion, particularly blood tests. Malignant tumors are typically associated with anemia, an elevated ESR, and sometimes leukocytosis, whereas benign tumors rarely cause such alterations.

In recent years, Laboratory Diagnostics of tumors (especially malignant ones) has been supplemented by an immunological method. This technique is widely used in diagnosing primary liver cancer and is based on the detection of embryonic globulin in the blood.

The search for specific reactions for cancer diagnosis is ongoing.

Radiological methods play a crucial role in diagnosing a range of tumor diseases (tumors of the esophagus, stomach, intestines, lungs, and Kidneys). These include radioscopy, radiography, tomography, fluorography, electroradiography, contrast radiography, angiography, lymphography, and fluoroscopy (x-ray television imaging).

The methods of radioscopy and radiography are universally known. Tomography involves cross-sectional X-ray Examination of body regions and is most commonly used to diagnose tumors of the thoracic organs and Mediastinum, allowing clinicians to determine the size of the tumor and its relationship to adjacent organs.

Fluorography has found widespread application in mass preventive screenings.

In recent years, video magnetic recording has been introduced; this involves recording the image obtained during x-ray television fluoroscopy for subsequent playback on a VCR.

The electroradiography method consists of acquiring the image not on x-ray film, but on a selenium plate with subsequent image transfer to a screen.

Contrast radiography utilizes various contrast agents administered intravenously, intra-arterially, into lymphatic vessels, fistulous tracts, or hollow organs, or taken orally. These include oil-based iodine preparations, Water-soluble organic iodine compounds, and emulsified halogenated oils. Air, oxygen, or nitrous oxide can also serve as contrast media. Occasionally, combined contrast techniques are employed (double contrast: barium mixture introduced into the stomach and air into the retroperitoneal space; triple contrast: air additionally introduced into the stomach).

Computed tomography is another key radiological diagnostic modality. The method is based on recording differences in the x-ray absorption coefficient across various tissues, providing reliable and timely detection of tumors in various locations (liver, brain, Pancreas, retroperitoneal space). Utilizing specialized equipment, physicians can visualize sequential cross-sections of The Human Body at any level and detect even the smallest tumors.

Oncologists also have nuclear magnetic Resonance (NMR) at their disposal as a diagnostic tool. It enables the detection of differences in the chemical and structural composition of normal versus tumor tissue. NMR helps recognize and differentiate the nature of pathological changes not only in tumors but also in certain precancerous conditions. For instance, transverse chest scans (NMR tomograms) clearly display the anatomy of blood vessels, the Trachea, and the bronchial tree (showing compression areas when these structures are constricted by a pathological process), as well as lymphatic vessels. Abdominal NMR tomograms clearly differentiate vascular elements, kidneys, Adrenal Glands, and the pancreas.

The affinity of various radionuclides for specific tissues forms the basis of radionuclide tumor diagnostics. For instance, radioactive iodine, once in the body, concentrates predominantly in The Thyroid Gland, whereas rose bengal dye and radioactive gold colloidal preparations concentrate in the reticuloendothelial system, etc.

The Essence of the method lies in the oral or intravenous administration of radiopharmaceuticals (nuclides) into the body, followed by measuring The rate of their passage through the studied organs or their distribution within organs and tissues using specialized recording devices. Radionuclide diagnostics utilize nuclides with low radiotoxicity—having a half-life ranging from 10 hours to several days.

Often, the degree of nuclide uptake by a specific organ is mapped out on paper, a technique known as scannography.

The laser diagnostic method for tumors involves the intravenous administration of a tumor marker (hematoporphyrin), which is selectively taken up by cancer cells and fluoresces under ultraviolet light from a krypton laser.

Thermometry is performed using a miniature thermometer—a radio transmitter designed to measure internal organ temperatures. The device is powered by an independent battery. It is swallowed and transmits radio signals regarding the Temperature of the digestive tract. According to R. Mikounis and I. Vavryk, in cases of Gastric Cancer, the temperature within the stomach is lower than that of a healthy organ.

Ultrasound examination is a non-invasive and relatively inexpensive method based on THE PRINCIPLE OF echolocation.

A distinct group of diagnostic Procedures in oncology comprises endoscopic methods. Their application has significantly reduced the rate of diagnostic errors. Special optical instruments are used to inspect certain Body Cavities and hollow organs from the inside (the abdominal and thoracic cavities, esophagus, stomach, intestines, Urinary Bladder, etc.). Endoscopy makes it possible to detect even minor surface changes on the mucous membrane.

In recent years, a number of new fiber-optic devices have been introduced for endoscopy, enabling physicians not only to examine hollow organs or cavities, but also to photograph specific areas and obtain tissue samples for biopsy.

Biopsies can be categorized as needle (puncture), simple (incisional), extended (excisional), or scraper biopsies. In a needle biopsy, the tumor is punctured with a needle to aspirate a few drops of tissue fluid for cytological analysis. In a simple biopsy, a small piece of tumor tissue is excised for histological examination, whereas in an extended biopsy, the entire tumor is removed. For instance, if a small tumor is found in the breast, it is excised and sent for immediate histological analysis. If the tumor proves benign, the surgery is concluded; however, if atypical cells are detected, The Scope of the surgical intervention is expanded.

When a tumor is ulcerated, a scraping is taken and the tissue is examined on a Glass slide.

Biopsy analysis based on the cellular composition of tissue imprints, smears, and aspirates makes it possible to determine the structure and even the grade of malignancy of a tumor.

A properly performed biopsy does not stimulate tumor growth or promote metastasis. The only exception is suspected melanoma, where a biopsy is contraindicated because it accelerates tumor growth and systemic dissemination.

BENIGN TUMORS

Benign tumors consist of Epithelial Tissue. These include papillomas, adenomas, and epithelial cysts.

Papillomas predominantly affect the skin and mucous membranes. They can be either congenital or acquired. When localized on mucous membranes, a papilloma may bleed, whereas on the skin, due to constant keratinization of the proliferating epidermis, it has the potential to transform into cancer. Papillomas grow as flat tumors, warts, villi, papillae, or cauliflower-like conglomerate masses. Acquired papillomas develop as a result of chronic irritation of the skin or mucous membranes (such as penile condylomata acuminata caused by irritation from gonorrheal discharge).

When a papilloma is located on the laryngeal mucosa, in the urinary bladder, or in the renal pelvis, it impairs organ function and causes Hemorrhage.

An adenoma is an epithelial or fibroepithelial tumor in which the epithelium lines tubular or cystic cavities, frequently accompanied by papillary proliferations. Unlike malignant growths, the epithelium here is clearly demarcated from the connective tissue stroma, and the cells exhibit only minimal polymorphism. Occasionally, the stroma—composed of connective tissue fibers—is so prominent that the lesion is classified as a fibroadenoma.

Adenomas are classified into papillary, cystic, tubular, and alveolar types.

Adenomas occur in all parts of the body where glandular tissue is present (the nasal mucosa, intestines, Mammary glands, Ovaries, thyroid gland, and Uterus). While retaining their histological benignity, they may occasionally ulcerate due to atrophy and erosion of their overlying surface.

Adenomas can function similarly to the normal organs from which they originate (e.g., a liver adenoma may produce bile, and a mammary adenoma may produce milk).

An epithelial cyst (cystis epithelialis) is a hollow lesion that develops as a result of epithelial proliferation. The majority of cysts are congenital in origin. They are subdivided into epidermal (dermoid) cysts and epithelial cysts arising from normal embryonic remnants.

Epidermal cysts, or dermoids (cystis dermoidalis, dermoidum), are sac-like formations that arise from the invagination of small areas of embryonic skin during early stages of Embryogenesis. Consequently, the inner wall of a dermoid cyst consists of Skin and its Appendages (sebaceous and Sweat Glands, hair). Together, these produce a paste-like mass that constitutes the Contents of the cyst. Dermoids can reach sizes of 6x4 cm. They grow very slowly and cause almost no discomfort to the patient, aside from cosmetic concerns. However, they are occasionally susceptible to infection. If pus breaks through to the exterior, it leads to the formation of fistulae. If a dermoid sac lacks hair, Sebaceous Glands, or sweat glands, it is classified as an epidermoid cyst, consisting solely of epidermis. Epidermoid cysts are most commonly located near the outer corner of the eye, the upper eyelid, the bridge of the Nose, the floor of the oral cavity, and the anterior mediastinum.

Epithelial cysts, in turn, are divided into acquired and congenital types. Acquired cysts typically form at the site of minor trauma as a result of the implantation of epidermal fragments into deeper tissues, whereas congenital ones arise from persistent embryonic remnants. These include median and lateral neck cysts (which develop from the unoblittered thyroglossal duct and branchial arches), as well as cysts of the urachal and bile ducts. These cysts may be closed or feature fistulous tracts through which secretions are discharged.

A retention cyst—or atheroma—must be distinguished from epithelial cysts. It occurs when the excretory duct of a sebaceous gland becomes blocked, leading to the accumulation of secretions. A characteristic feature of an atheroma is its growth within the thickness of the skin, to which it is tightly adherent.

An example of an endothelial tumor is the endothelioma. It develops from the endothelium of lymphatic or blood vessels and is most commonly located in the skin, and less frequently in other organs (the Spleen, stomach, pharynx, and uterus).

Tumors composed of connective tissue include fibromas, lipomas, chondromas, and osteomas.

A fibroma develops from Fibrous connective tissue and contains fibroblasts. It differs from normal connective tissue by the polymorphism of its fibers and cells. It is localized in the skin, subcutaneous tissue, mammary gland, Mandible, and other organs containing connective tissue.

Fibromas are divided into Hard and Soft types. A hard fibroma contains spindle-shaped cells resembling fibroblasts or fibrocytes and Collagen fibers in addition to fibrous connective tissue, whereas a soft fibroma incorporates elements of adipose tissue, blood vessels, or cysts.

A fibroma is mobile, smooth, and not fused with adjacent tissues.

A soft fibroma, which typically localizes on the skin or mucous membranes (such as the nose, nasopharynx, or larynx), is pedunculated and referred to as a polyp. Epulides are also classified among soft fibromas; they develop between the Teeth from the connective tissue of the gingiva or periosteum of the jaws, are highly vascularized, and tend to bleed frequently.

Hard fibromas generally originate in the subcutaneous tissue. When local tissue components are involved in their formation, mixed tumors arise, such as fibrolipoma, fibroadenoma, and neurofibroma.

Fibromas localized within fascias and aponeuroses are termed desmoids and are most commonly found on the posterior wall of the rectus abdominis Muscle.

A Lipoma consists of adipose tissue with a minimal amount of connective tissue and is enclosed within a capsule. It is typically situated in the subcutaneous layer as a rounded, well-circumscribed,

soft mass. Palpation reveals a lobular structure. Lipomas grow slowly and usually occur as solitary lesions, although multiple tumors are also possible (lipomatosis). Occasionally, they can attain considerable sizes, in which case the tumors are composed of large lobules and are predominantly located on the extremities and the anterior abdominal wall.

A chondroma is a tumor originating from cartilaginous tissue, typically localizing in bones that contained Cartilage during early stages of embryogenesis. Chondromas frequently begin to grow following trauma. Depending on whether the tumor develops within the bone interior or on its outer surface, central and peripheral chondromas are distinguished. Chondromas most commonly develop in the metaphyses of long tubular bones, but can also occur in the pelvic bones, scapula, and mandible. Multiple chondromas are often found in the short BONES OF THE Phalanges of the hand.

Enchondromas grow inside the bone, destroying it to the extent that eventually only a thin ossified periosteum remains, whereas peripheral chondromas leave the bone intact. Tumors developing in long tubular bones can cause pathological fractures and pose a risk due to the potential for malignant transformation into chondrosarcoma. Chondromas are generally small, although they can occasionally reach significant sizes.

Osteomas originate from osseous tissue and develop spontaneously without an apparent cause. The proliferation of Bone tissue following trauma or inflammatory processes is referred to as an exostosis. Osteomas typically develop at a young age and follow an asymptomatic course. They are usually solitary, with multiple tumors being rare. An osteoma originating from the compact bone is termed peripheral, whereas one arising from the spongy substance is designated as central.

Occasionally, pressure exerted by an osteoma on adjacent nerves may cause pain. Palpation reveals a hard, fixed mass connected to the bone, and the diagnosis is confirmed radiographically.

Tumors of vascular tissue.

A hemangioma is a congenital tumor that most frequently localizes in the sites of embryonic clefts: on the lips, Cheeks, and within the oral cavity, although it may also develop in other areas (such as Internal Organs, particularly the liver, and less commonly in Bones and joints). It does not grow in tissues devoid of blood vessels. All birthmarks containing a certain proportion of capillaries are classified as hemangiomas.

Hemangiomas are categorized into capillary, cavernous, and plexiform (branching) types. A capillary hemangioma is characterized by a small, bluish-red skin spot that disappears upon pressure. This spot represents a network of dilated capillaries (birthmark). Occasionally, a hemangioma may involve a substantial portion of the face.

A cavernous hemangioma has a spongy structure with blood-filled spaces. It is most commonly located subcutaneously, showing through healthy or thinned skin, and is characterized by deep growth and invasion into the surrounding muscles. Such tumors can significantly deform the affected body parts. Upon palpation, a cavernous hemangioma feels soft; it flattens upon compression and subsequently refills. While these tumors often grow rapidly, their growth may also arrest.

A plexiform (branching) hemangioma is a tumor composed of markedly dilated, beaded, tortuous vessels. It protrudes above the skin surface as a flat swelling and is visible through the skin. Palpation reveals pulsation, and Auscultation detects bruits (resembling a blowing or buzzing sound). When localized on the HEAD, a hemangioma is accompanied by a sensation of constant noise. Branching hemangiomas are typically congenital.

Hemangiomas are susceptible to rupture and may be complicated by hemorrhage.

A lymphangioma is a tumor consisting of lymphatic vessels, which is usually congenital in nature and less common than a hemangioma. Lymphangiomas can be capillary, cavernous, or cystic, and are typically located on the face, specifically the lips, cheeks, and Tongue. Occasionally, they attain massive proportions, causing facial disfigurement.

A capillary (simple) lymphangioma appears as tiny nodules that disappear upon compression.

A cavernous lymphangioma presents as a diffuse or circumscribed swelling of a soft, doughy consistency that flattens upon pressure and reappears once the pressure is released. The overlying skin remains unchanged. It is most frequently localized within the thickness of the lips and tongue.

A cystic lymphangioma resembles a cyst and can sometimes reach large sizes, containing a serous, milky-white fluid. It is most commonly found in the neck, mesentery of the intestines, and retroperitoneal space. When located superficially, a fluid thrill (fluctuation) sign may be elicited. Puncture with Analysis of the contents aids in diagnosis.

Tumors arising from muscular tissue are termed myomas, which develop in either striated muscle (rhabdomyoma) or smooth muscle (leiomyoma).

Pure rhabdomyomas are rare (occurring predominantly in the myocardium) and more frequently form a component of mixed tumors of the Genitourinary System and parotid gland, or grow within the mediastinum. A pure rhabdomyoma is a well-encapsulated tumor whose color is somewhat paler than that of normal muscle. It is considered to be of embryonic origin, arising from myoblasts.

In contrast to rhabdomyomas, leiomyomas are common and can be found in any organ containing smooth muscle. They also incorporate connective tissue fibers and blood vessels. Leiomyomas are most frequently localized in the uterus, and less commonly in the gastrointestinal tract, urinary bladder, Prostate Gland, and skin.

Leiomyomas vary significantly in size, ranging from tiny nodules to 10–15 cm in diameter, and are frequently complicated by hemorrhage and malignant transformation.

Tumors of the nervous system are classified as follows: 1) tumors originating from the mesenchymal tissue of the central and peripheral nervous systems (glioma and neurinoma); 2) tumors arising from neural tissue (ganglioneuroma).

Gliomas are solitary, well-circumscribed, rounded tumors localized in the brain and retina. They consist of neuroglial cells with processes and vary widely in size, ranging from minute nodules to masses occupying an entire cerebral hemisphere. Cerebral gliomas present with clinical manifestations of a brain tumor depending on their localization. When located in the Spinal Cord, they may cause sensory and trophic disorders in the periphery. Ocular gliomas are malignant in nature, leading to the destruction of the Orbit.

Neurinoma develops in the peripheral nerves and posterior roots of the spinal cord as numerous soft nodes of varying sizes (sometimes up to 10 X 10 cm). The clinical picture is characterized by the compression of the corresponding nerve trunks.

Ganglioneuroma consists of Unmyelinated nerve fibers and ganglion cells. It is relatively rare. It is a nodular, well-demarcated tumor protruding into the lumen of the cerebral ventricles or the central canal of the spinal cord. Clinically, it resembles a brain or spinal cord tumor.

Special attention should be paid to so-called mixed tumors. They are of embryonic origin and consist of several tissue types. Simple and complex mixed tumors are distinguished. A simple tumor has 2 germ layers (the middle one — mesoderm, and either ectoderm or endoderm), while a complex one has 3.

A simple mixed tumor comprises cartilaginous, mucous, and adipose tissues with epithelial or glandular formations. They more commonly develop in the parotid gland, mammary gland, and Urogenital System. A mixed Kidney tumor, which usually develops in childhood and adolescence, is malignant in nature.

Complex mixed tumors are divided into teratoid tumors (teratoids) and teratomas.

A teratoid tumor resembles a dermoid cyst, but its structure is more complex because it contains not only skin with its elements, but also bones, teeth, and hair. It develops more frequently in the Ovary.

Teratoma is a tumor that arises as a result of impaired embryonic development. It includes tissues that microscopically, and sometimes macroscopically, resemble the tissues of various organs (skin with its appendages, muscles, teeth, Nervous Tissue, bones, cartilage). Tissues of the liver, kidney, pancreas, and Heart are less common.

Most often, a teratoma appears as microcystic formations of varying sizes. It localizes in the ovary, Pituitary Gland, eye orbit, neck region, oral cavity, thyroid gland, mediastinum, coccygeal region, Abdominal cavity, etc. However, the sacrococcygeal region is the most common site for teratomas. The clinical picture of a teratoma depends on its location.

MALIGNANT TUMORS

Cancer (cancer, carcinoma) is a malignant tumor originating from epithelial tissue. It accounts for 90% of all malignant tumors. It more frequently affects elderly and old-age individuals. In recent decades, there has been a trend toward cancer occurring at a younger age, which can be explained by better diagnostics. The tumor can grow in any organ containing epithelial tissue. Women are more frequently affected by cancer of the uterus, breast, stomach, lungs, thyroid, liver, and Gallbladder; men — by cancer of the stomach, esophagus, lower lip, larynx, and lungs.

In recent years, cancer incidence has increased mainly due to neoplasms of the breast, liver, bronchi, trachea, and thyroid gland. At the same time, the incidence of cancer of the stomach, esophagus, lower lip, and cervix has decreased.

Today, lung and bronchial cancer ranks first among oncological diseases, skin cancer ranks second, stomach cancer third, and breast cancer fourth.

Depending on the nature of the cells comprising the tumor, squamous cell and columnar cell carcinomas are distinguished. The latter may present as solid or glandular carcinoma. A tumor containing an abundant amount of connective tissue is called scirrhus, while one with scant connective tissue is termed medullary carcinoma.

A number of classifications have been proposed for malignant tumors, primarily cancer. Thus, all patients are divided into several clinical groups:

Ia — patients with suspected oncological disease;

Ib — patients with precancerous conditions (benign tumors, trophic ulcers, mastopathy, chronic recurrent Bronchitis, etc.);

II — patients with malignant tumors eligible for special treatment (Radiation therapy, Chemotherapy);

IIa — patients with malignant tumors requiring radical treatment (surgical, radiation);

III — virtually healthy individuals cured of a malignant tumor (showing no relapses or metastases);

IV — patients with malignant tumors in late stages of the disease who are prescribed palliative (symptomatic) treatment.

Depending on the outcomes of therapy, patients are transferred from one clinical group to another.

The stages of the disease characterize the extent of cancer spread in a specific patient.

Since 1956, a general staging system for malignant tumors has been adopted:

I — localized tumor without involvement of adjacent LYMPH NODES AND without invasion into deeper tissues. No metastases;

II — relatively small tumor, more than 2 cm in diameter, with solitary mobile metastases in nearby regional lymph nodes;

III — a tumor larger than 5 cm in diameter, invading adjacent tissues and limiting organ mobility. Metastases in neighboring lymph nodes form a fixed conglomerate;

IV — a tumor of any size with distant metastases or deep invasion into adjacent organs and tissues, accompanied by severe physical exhaustion.

The limitation of this classification is that it often fails to characterize the extent of malignant spread when localized in internal organs (such as the stomach, intestines, lungs, uterus, etc.) and does not account for early, preclinical forms of cancer.

To facilitate a better understanding of cancer growth patterns among oncologists worldwide, the International Union Against Cancer adopted the TNM classification of malignant tumors in 1958.

T — tumor, N — noduli, M — metastasis.

A number added to each of these components indicates the extent of the malignant disease.

T — primary tumor. Tis (in situ) refers to pre-invasive, intraepithelial cancer.

T₀ — no evidence of primary tumor (only metastases are detected).

T₁ — a small tumor located On the surface of an organ or within its parenchyma, not fused with adjacent tissues.

T₂ — a small-sized tumor (up to 2 cm) with infiltration of deeper tissue layers, extending to neighboring anatomical regions without impairing the mobility of the organ itself. In larger organs (such as the breast), the tumor reaches up to 5 cm.

T3 — a tumor invading deep into the organ and partially restricting its mobility. For smaller organs, the diameter exceeds 2 cm; for larger ones, it exceeds 5 cm.

T₄ — a tumor involving adjacent organs and completely restricting their mobility.

It must be emphasized that due to structural differences among organs, T₁₂₃₄ may have varying characteristics for each of them.

N — regional lymph nodes.

N₀ — regional lymph nodes cannot be assessed. If microscopic examination of the removed lymph node reveals metastases, it is designated as N₀₊.

N₁ — one or several enlarged lymph nodes (N — presence of metastases is questionable, N_1b — presence of metastases is substantiated).

N₂ — a group of enlarged, matted lymph nodes. This category also distinguishes cases with histologically unconfirmed metastases.

N₃ — a group of overtly metastatic lymph nodes that are fixed or located in distant areas of regional metastasis (e.g., supraclavicular region in breast cancer).

N₄ — metastases in non-regional lymph nodes.

N_x — lymph node status cannot be assessed (stomach, rectum, lungs); the diagnosis of metastasis remains unconfirmed.

Regarding the N parameter, it should be noted that its value in determining the extent of metastatic spread is limited. For instance, palpation of regional lymph nodes does not confirm the presence of a tumor. Non-palpable nodes may contain metastases, whereas palpable ones do not necessarily do so, as this can be the result of hyperplasia. Histological examination remains the only reliable method, which is why additional markers are introduced (N₀, N_0x).

M — distant metastases.

M₀ — no distant metastases detected. It should also be noted that the symbol M₀ cannot categorically rule out distant metastases in certain organs, as the latter may harbor occult, widely disseminated microscopic tumor deposits.

M₁ — distant metastases present (for more precise localization, they are designated with symbols such as M_pul — lungs, M_oss — bones, M_hep — liver, etc.).

M_x — presence or absence of distant metastases cannot be assessed by available diagnostic methods.

Given certain Limitations of the T,N,M system, it has been modified.

Specifically, the histological grade of the tumor is distinguished (G₁, G₂, G₃, G_x),

while for cancers localized in the stomach and intestines, the depth of invasion into hollow organs is specified (P_1,2,3,4). P₁ represents cancer infiltrating only the mucosa; P₂, cancer infiltrating the mucosa and submucosa; P₃, spreading to the subserosal layer; and P₄, tumor infiltration of the serosa extending beyond the organ wall.

Comparing the staging Classification of tumors with the International Classification yields the following correlations:

Stage I — T₁, N₀, M₀ — the tumor is confined to The Organ of origin. No metastases are present. Operable. Five-year survival rates reach 70–90%;

Stage II — T₂, N₁, M₀ — the tumor does not extend beyond the organ, with single metastases in adjacent regional lymph nodes. Operable, though radical cure cannot be guaranteed with absolute certainty. Five-year survival is achieved in nearly 50% of patients;

Stage III — T₃, N₂, M₀ — a large tumor invading adjacent tissues and organs. Numerous metastases are present in regional lymph nodes. Not amenable to radical Surgical treatment;

Stage IV — T₄, N₃, M₁ — the tumor is inoperable, with a very poor prognosis.

Malignant tumors arising from connective tissue are called sarcomas (sarcoma). They may include cartilaginous, osseous, and neural elements, in which case they are designated accordingly—osteosarcoma, chondrosarcoma, etc.

The term "sarcoma" originates from the Greek word "sarcoma", meaning "flesh" (on cross-section, the tumor resembles fish flesh). Sarcoma refers to any malignant tumor of non-epithelial origin.

Sarcomas are rarely congenital; they are more commonly acquired. They develop from the periosteum, endosteum, and perivascular elements.

Three types of sarcomas are distinguished: round-cell, spindle-cell, and giant-cell.

Round-cell sarcomas are the most malignant because they consist of the least mature cells. Giant-cell sarcomas are less malignant. Spindle-cell sarcomas are the most mature in their cellular composition and are therefore the least malignant.

Sarcoma appears as a nodular, lobulated tumor of varying consistency (from soft to firm), fused with adjacent tissues. Necrosis frequently develops in the center of the tumor, leading to softening. It contains hemorrhagic material.

Unlike carcinoma, systemic manifestations (cachexia) in sarcoma are less pronounced or absent altogether (depending on the tumor location).

Sarcoma is highly malignant, growing faster than carcinoma and destroying all adjacent tissues, including bone. It has a high propensity for distant metastasis. Metastases typically spread via hematogenous routes.

Sarcomas most frequently affect bones (18.3%), soft tissues (15.3%), and Lymphoid organs (14.9%), followed by the FEMALE REPRODUCTIVE ORGANS, skin, digestive tract, and others.

TREATMENT OF TUMORS

Benign tumors are in most cases subject to surgical treatment—removal. On the one hand, this is a therapeutic method; on the other hand, it is prophylactic given the potential for malignant transformation.

The treatment of malignant tumors is complex. Today, the main modalities of therapy include surgery, radiation therapy, chemotherapy, hormone therapy, and supportive care. Other methods used to treat malignant neoplasms include immunotherapy, laser irradiation, cryosurgery, and hyperthermia.

Surgery remains the primary treatment for the majority of malignant tumors, with all other modalities being adjuvant.

Surgeries for patients with malignant tumors may be classified as: standard radical, extended, combined, super-radical, palliative (or conditionally radical), and symptomatic.

A standard radical operation aims to restore the patient's health (following the Procedure, patients are considered practically healthy and assigned to clinical group III). The procedure involves the removal of the tumor within healthy tissue margins along with regional lymph nodes, and frequently the organ of origin, while strictly adhering to the principles of ablantics and antiblantics.

An extended operation involves the removal of an organ or part of it (along with the tumor) by expanding the margins of resection and removing an additional group of regional metastases.

In a combined operation, alongside the organ affected by the malignant tumor, an adjacent organ or a portion of it invaded by the tumor is also removed (e.g., resection of the liver margin in cases of gastric tumor invasion; splenectomy during gastric resection).

An ultraradical operation involves not only removing the tumor-bearing organ but also adjacent structures invaded by the growth (such as Hysterectomy combined with cystectomy and proctectomy).

Palliative, or conditionally radical, surgery aims to remove the tumor, though not always within healthy tissue margins and without regional lymph node dissection (e.g., in cases of a decaying, malodorous breast cancer with distant metastases that preclude a radical procedure, only a simple mastectomy of the tumor-bearing breast is performed).

Symptomatic surgery focuses not on tumor resection, but on alleviating the most debilitating symptoms (such as gastrojejunostomy for an inoperable pyloric cancer complicated by obstruction).

For certain cancer localizations, surgeons sometimes operate on organs unaffected by the malignant process to inhibit tumor growth or prevent recurrence (e.g., oophorectomy in breast cancer or orchiectomy in prostate cancer).

During surgery for malignant tumors, adherence to the principles of ablastic and antiblastic technique is essential.

Ablastic surgery is an operative approach designed to remove all tumor elements within healthy tissue margins. To ensure ablastics, surgeons follow the principles of regional zoning and compartmentalization. Regional zoning involves accounting for the primary tumor's spread patterns and regional lymph node metastasis. Compartmentalization is achieved by operating within anatomical fascial-adipose and serous-adipose compartments that act as natural barriers limiting tumor dissemination.

Antiblastic surgery involves measures aimed at preventing the dissemination and implantation of cancer cells within the surgical wound, as well as destroying them.

These measures include: early ligation of the venous vessels draining the tumor; isolating the tumor-bearing organ with gauze Sponges; frequent changes of gloves and instruments; and the use of electrosurgery, electrocoagulation, or irrigation of the wound and adjacent cavities with cetrimide solution (1:500) to destroy free-floating cells.

The bloodless laser scalpel has yielded promising intraoperative results. A radiation power of several tens of watts concentrated on an area of 1 mm² is sufficient to cut any tissue, seal blood vessels, and prevent the spread of cancer cells.

The success of the operation depends on timely intervention, proper technique Selection, and the radicality of tumor removal.

Surgical treatment is applicable to tumors of all localizations.

Absolute contraindications to surgery include: the presence of distant metastases; tumor invasion into vital organs; extensive tumor involvement requiring major, traumatic procedures in a debilitated patient; and severe concomitant comorbidities (decompensated heart defects, pulmonary insufficiency, marked hepatic or Renal Dysfunction).

Surgical treatment is not indicated when cancer can be cured by other modalities, such as radiation therapy (e.g., lip cancer).

Surgery is frequently combined with other treatment modalities for malignant tumors, either as neoadjuvant therapy prior to surgery or in the postoperative period.

Radiation therapy. X-rays and radium rays affect healthy and pathological cells differently. Pathologically altered cells exhibit higher radiosensitivity and perish under irradiation. This is particularly true for immature tumor forms (carcinoma, sarcoma). The difference in radiosensitivity between malignant tumors and surrounding tissues defines the therapeutic radiosensitivity window. Radiation effects extend beyond the direct destruction of cancer cells; they are further compromised by cellular breakdown products and compression by the connective tissue proliferating post-irradiation.

Radiation therapy can be utilized as a standalone radical treatment (for skin, lip, or cervical cancer) or as an adjuvant therapy combined with surgery and pharmacotherapy.

Radiation therapy can occasionally convert an inoperable case into an operable one.

Radiation therapy may be employed preoperatively to prepare the patient for surgery, intraoperatively to achieve antiblastic effects, and postoperatively to prevent recurrences and metastases while reinforcing the radicality of the surgical intervention.

Pre-radiation measures aimed at increasing tumor radiosensitivity are sometimes applied, including Hyperbaric Oxygenation and the administration of radiosensitizing agents.

Radiation therapy can be administered via various methods, specifically:

1) external, percutaneous irradiation. Depending on the distance from the radiation source to the skin surface, it may be contact (the source lies directly on the skin or tumor), short-distance (source-to-skin distance up to 25 cm), or long-distance (from 30 cm to 4 m);

2) internal irradiation. This may be interstitial (the radiation source is placed directly within the tumor) or intracavitary (the source is introduced into anatomical cavities, such as the esophagus or urinary bladder).

Radiotherapy utilizes short-wave gamma rays emitted by various nuclides (cobalt, iodine, gold, phosphorus, sodium, etc.), whose energy and penetrating power significantly exceed those of X-rays.

X-ray or gamma radiation exposure is measured using exposure dose (dose in air)—measured in roentgens (R)—and absorbed dose—measured in rads.

Various irradiation regimens are employed: single-dose—150–200 rad (rarely used); continuous (interstitial, intracavitary, and surface application) with a total dose of 5000–6000 rad; low-fractionated (teletherapy gamma-therapy), where the patient receives 200–550 rad per session and 400–600 rad per week over a 4–6 week course; moderate-fractionated irradiation, with a single dose of 400–600 rad administered 2–3 times per week; and concentrated irradiation, with a single dose of 400–600 rad given every 2–3 days, reaching a total dose of 1000–1200 rad.

In oncological practice, split-course gamma therapy has become widely used. The total radiation dose is divided into two courses administered with an interval of 2—3 weeks. The total radiation dose is increased by 1000—1500 rads compared to the standard protocol.

Prolonged radiation exposure can cause a number of adverse systemic reactions: the functioning of the cardiovascular, endocrine, and nervous systems is impaired; patients may experience general weakness, insomnia, tachycardia, vomiting, diarrhea, loss of working capacity, and loss of appetite. Blood tests reveal leukopenia, anemia, lymphopenia, and thrombocytopenia.

Irradiated individuals show increased susceptibility to infections. Local inflammatory reactions of varying intensity, ranging up to necrosis, may occur on the skin within the radiation field. To prevent this complication, various skin-protective agents (dermatoprotectors) are used.

Radiation therapy is indicated for all malignant tumors except for cancer of the stomach, liver, colon, pancreas, and other abdominal organs. Contraindications to radiation therapy include the patient's severe general condition, marked blood abnormalities, and cardiovascular failure.

Hormone therapy for malignant tumors aims to suppress the internal secretion of those endocrine glands whose products can stimulate the growth and proliferation of malignant cells. It is indicated for hormone-dependent tumors.

Hormone-dependent tumors require specific hormonal influences for their development. Such tumors include certain types of cancer of the breast, ovaries, Testes, prostate, thyroid, uterus, endometrium, larynx, as well as lymphadenosis.

Hormone therapy involves the administration of hormones that act as tumor antagonists: for men—estrogens (stilbestrol, synestrol, estradion, honvan); for women—androgens (testosterone propionate, methyltestosterone propionate).

Other prescribed hormones include adrenal cortex preparations, namely corticosteroids. Hydrocortisone and cortisone are used in acute and chronic leukemias, Hodgkin's disease, and breast cancer. More active synthetic preparations include prednisolone and prednisone.

Adrenocorticotropic hormone is also used in the treatment of leukemias.

The Effect of hormone therapy varies: sometimes it is short-lived, while in other cases it persists for several years.

Cancer chemotherapy cannot replace surgical and radiation treatments, but merely complements them. It is used as a standalone method when radical treatment modalities have proven ineffective or are contraindicated.

Medications can sometimes render an inoperable tumor operable or sensitize the patient's body to the effects of radiation.

The action of chemotherapeutic agents is based on two principles: a) destruction of tumor cells without damaging healthy ones (cytotoxic effect); b) action on cellular mutation by interfering with the formation of protein compounds in the Cell Nucleus, and consequently of Chromosomes and genes (cytostatic effect).

Chemotherapeutic drugs have a particularly pronounced effect on dispersed neoplastic cells and a weak effect on established solid tumors. Therefore, it has been proposed to first surgically remove the tumor and subsequently destroy the cells circulating in the blood or seeded in organs via oral, intramuscular, or intravenous administration of medications.

Chemotherapy yields favorable outcomes in tumors such as testicular seminoma, skin cancer, Ovarian cancer, Hodgkin's disease, and others. However, it is ineffective against tumors of the digestive tract and lungs.

Antitumor activity is exhibited by alkylating agents, antimetabolites, certain plant-derived preparations, Antibiotics, and specific enzymes.

To date, A large number of chemical compounds have been synthesized. About 50 of them have been selected for clinical use, including up to 30 active antitumor drugs that exert a pronounced therapeutic effect by disrupting mitosis metabolism, DNA and RNA Synthesis within tumor cells, and other mechanisms.

All antitumor drugs can be divided into several groups:

1) chlorethylamines and ethylamines (alkylating agents)—cyclophosphamide, sarcolysin, dopan, novembiquine, thiophosphamide, benzotef;

2) antimetabolites—methotrexate (amethopterin), 5-fluorouracil, ftorafur, thioguanine, 6-mercaptopurine, cytosar;

3) plant-derived preparations—colchamine, oncovin, vincristine, vinblastine. These are mitotic poisons;

4) Introduction/45.html">Antitumor Antibiotics—aurantin, chrysomallin, mithramycin, doxorubicin, carminomycin, mitomycin C, dactinomycin;

5) miscellaneous synthetic compounds (cisplatin, procarbazine, mitoxantrone, etc.).

Chemotherapeutic drugs are used in the following cases:

1) for malignant tumors when surgical intervention is impossible (leukemia, hemoblastosis, chorioncarcinoma, rhabdomyosarcoma);

2) in combination with surgical or radiation treatment (breast, testicular, and prostate cancers, among others);

3) for the prevention of metastasis (following radical surgery — adjuvant chemotherapy) in breast and testicular cancer, as well as in the preoperative period to convert an inoperable tumor into an operable one;

4) for the palliative treatment of malignant tumors.

Chemotherapeutic agents are administered into the body via various routes: orally, vascularly, or into body cavities (abdominal, thoracic).

The most effective method is regional intra-arterial infusion via a catheter inserted into the artery, which allows for a high concentration of the drug to be achieved within the tumor while reducing its systemic toxicity.

In addition to intra-arterial infusion, intra-arterial perfusion is also utilized. This method involves isolating the organ containing the tumor from the general circulation and connecting it instead to a heart-lung machine containing the antineoplastic agent. This technique is applied when tumors are localized in the extremities, head, neck, or pelvic region. Chemotherapy is administered in courses of varying duration.

The use of antineoplastic drugs may be accompanied by side effects and complications, namely: Bone Marrow suppression (myelosuppression), dyspeptic symptoms (nausea, vomiting, diarrhea) resulting from ulcerative and necrotic Changes in the mucous membrane of the digestive tract, and toxic damage to the skin and its appendages (hair loss — alopecia). Many drugs also exert toxic effects on the pulmonary and nervous systems, the liver, and the blood clotting system.

Chemotherapy is contraindicated in cachectic patients with disseminated tumor processes, primary suppressed hematopoiesis (fewer than 3,000 leukocytes and 100,000 platelets), individuals with concurrent diseases of The Cardiovascular system, kidneys, or liver, and those with purulent processes or tuberculosis in the active stage.

Immunotherapy. This method of treating malignant tumors was proposed in the 1960s.

The foundation of immunotherapy lies in the fact that every tumor contains unique antigens inherent only to it, which differ from the antigens of the tissue from which it originates. These antigens are referred to as tumor-specific antigens.

Treatment with Antibodies specific to a given tumor can inhibit its growth.

A distinction is made between active and passive immunotherapy.

Active immunotherapy involves the administration of tumor cells (which may be the patient's own cells) that have been killed by irradiation.

In passive immunotherapy, preformed antibodies are administered to the patient. Passive immunotherapy can be specific (administration of antitumor antibodies) or nonspecific (administration of nonspecific antibodies, such as gamma globulin).

Laser therapy. In 1955, Nobel laureates N. Basov, A. Prokhorov, and C. Townes laid the foundations of a new scientific direction — quantum electronics. This became possible thanks to the invention of new radiation sources: optical quantum generators, or lasers.

Laser beams are highly directional, allowing a large amount of light energy to be concentrated in a very small area (a few microns). A very high temperature is generated at the point of impact, enabling the beam to destroy tumor cells.

Research by R. Kavetsky and co-workers demonstrated that along the path of the laser beam in tissues, changes occur that resemble electrosurgical necrosis.

The aforementioned findings provided the rationale for utilizing the laser beam in oncological practice — both for the destruction of certain types of tumors and during surgery to achieve ablation and anti-blastosis.

Laser therapy is used to treat skin cancer, melanoma of the auricle and nose, localized melanoma of the oral cavity, and certain malignant tumors of the larynx.

Cryosurgery. Since ancient times, low temperatures have been used to treat various pathological processes. In oncology, this method began to be employed in the late 1970s.

Cold enables the complete destruction of pathological tissue located either on the body's surface or deep within any organ. Access to deeply situated tissues is achieved using a thin cryosurgical instrument. Local cryosurgical action on tissues is painless. The necrosis zone induces only a minor perifocal reaction. Freezing occurs without damaging healthy tissues, and the area of cryodestruction heals rapidly.

Among the disadvantages of the cryosurgical method is the fact that a single freeze often fails to eradicate all cancer cells, thereby necessitating repeated interventions.

Cryosurgery is used to treat cancers of the skin, lip, oral cavity, and tongue, as well as hemangiomas, etc.

Hyperthermia is one of the approaches used in tumor treatment. It involves raising the patient's body temperature. Tumor cells have a high demand for glucose, absorbing it 16 times faster than normal cells. If cancer cells are 'supersaturated' with glucose to 4 times the normal level (an excess of glucose is harmless to healthy cells), lactic acid accumulates within the tumor. This leads to overacidification of the tumor cells, making them more vulnerable to heat. At 42 °C, such tumor cells perish, whereas normal cells can withstand this temperature for several hours.

Palliative treatment is most frequently employed for stage IV malignant tumors. Its purpose is to support the Functions of various organs and systems (cardiovascular, respiratory, nervous, etc.), alleviate the patient's suffering, and prolong their life.

Symptomatic treatment is of particular importance in elderly patients with comorbid conditions.

Since cancer patients frequently develop anemia, periodic blood transfusions, packed red Blood Cells, and plasma are indicated.

Detoxification therapy, correction of water-electrolyte and acid-base balance, administration of lipotropic agents (lipocaic, Choline, Methionine), B-group Vitamins, ascorbic acid, and anabolic hormones (nerobOL, testosterone propionate) should be performed.

To prevent pulmonary complications, bronchodilators, respiratory exercises, and Oxygen therapy are prescribed. To improve cardiovascular function, cardiac medications (cordiamin, cocarboxylase, corglycon) are administered.

For bedridden patients, frequent repositioning and skin rubbing are used to prevent pressure ulcers. Physiological functions (urination and bowel movements) must be monitored and should remain regular.

In the presence of pain syndrome, analgesics (promedol, morphine, analgin, etc.) and sedatives (moxiron, elenium, tazepam) are administered.

It is desirable to achieve complete pain relief. Efforts should be made to prevent pain from occurring rather than merely alleviating it.

Treatment of patients with malignant tumors in general, and in stage IV in particular, requires strict adherence to deontological principles. If the patient's death is inevitable, everything must be done during these final days and weeks to ensure the patient does not feel lonely. All medical staff must be prepared to help the patient die with dignity. In some countries, specialized hospitals—hospices—exist for incurably ill cancer patients. Every condition is created for them to spend the final period of their lives in the best possible way, without feeling the approach of death.

Thus, the treatment of cancer patients can be combined, multimodal, and comprehensive. Combined therapy involves the simultaneous use of homogeneous methods with different Mechanisms of action or different technical approaches (combining chemical agents with different mechanisms of action; external and interstitial irradiation).

Multimodal therapy involves the application of two different treatment methods (surgery and radiation therapy; surgery and medical therapy).

When three or more methods are used for the treatment of cancer patients, it is considered comprehensive (surgical, radiation, and medical treatment; surgical, medical, and hormonal treatment).

The survival time of patients with malignant tumors after treatment varies. It depends on the nature and localization of the tumor, its histological structure, and the timing of treatment.

The degree of "cure" is assessed by survival rates at various time intervals post-treatment. Typically, evaluation is performed at 5 and 10 years. For individual cases, survival curves (life tables) can be constructed and compared with similar curves of healthy individuals (A.P.M. Forrest, D.S. Carper, I.B. Macleod, 1994).

PREVENTION OF CANCER

Cancer prevention is one of the most important tasks of modern medicine.

Clinical research and observations demonstrate the feasibility of preventing malignant tumors.

Following the discovery of X-rays and their application in medicine, radiologists frequently developed skin cancer. Once protective equipment (gloves, aprons, goggles, screens) capable of blocking radiation was introduced, this form of cancer was no longer observed.

Consequently, through preventive measures and occupational health and safety in the workplace, the onset of many forms of cancer can be prevented.

Another pathway for cancer prevention is the timely detection and treatment of precancerous conditions.

The third direction in the prevention of malignant tumors is combating harmful habits, with tobacco smoking taking top priority.

According to clinical observations, lung cancer mortality among smokers is 20 times higher compared to non-smokers. Furthermore, they have a higher incidence of gastric and duodenal ulcers, pulmonary emphysema, and cardiovascular diseases.

M. Kuzin divides all measures for the prevention of malignant tumors into three groups.

1. Personal prevention. Here, great importance is attached to the patient's monitoring of their own health status.

2. Medical prevention. This involves physician supervision of patients at high risk who are prone to developing malignant processes, ensuring their timely rehabilitation.

3. General prevention. This consists of purifying the air, water, soil, and food products from carcinogenic substances.

All of the measures listed above are currently of great importance—and will remain so in the future—for reducing cancer morbidity. After all, medicine is already capable of preventing the development of cancer in the majority of cases.