CANCER (cancer) — the malignant tumor developing from epithelial fabric. In foreign, preferential Anglo-American, literature the term is applied sometimes in wider value to designation of set of all malignant tumors.
Attempts to give rather accurate definition to the concept «cancer» were not crowned with success yet that is connected with lack of full data on its nature. It is possible to say that R. is the pathological growth of the atypical epithelial cells replacing having the autonomous progressing irreversible nature of growth and infiltriruyushchy normal fabrics only. It should be noted that almost all from the specified R.'s features cannot be considered as absolute. The forms P. which growth is not autonomous are had, and depends on some hormones and other factors of an organism. The concept «progressing» does not extend to all cases of River too. Some types and R.'s stages can exist vaguely long at the level registered at primary diagnostic testing. without finding signs of local growth and without giving metastasises (see. Innidiation ). Irreversibility cannot be also considered as absolute quality of R. since in some cases at animals and occasionally at the person R. can spontaneously regress.
As a disease of the person R. it is known through many centuries. The term «carcinoma» is for the first time offered by K. Galen for designation of a breast cancer that, apparently, it was caused by analogy between tumoral deformation, the drawing of expanded venous vessels at a breast cancer and outward of representatives of a class of Crustacea — cancer, a crab. Among causes of death of R. it is for the first time mentioned in 1629 in «The bill of mortality» which was annually issued in England. In 1775 P. Pott described a carcinoma cutaneum of a scrotum at chimney sweeps what was the first publication about professional cancer. In 1844 R. Stern published the message on cancer a pier of internal gland and cancer of a uterus at female residents of Verona (Italy). In 1876 M. A. Novinsky for the first time showed a possibility of transplantation of tumors at animals, having laid the foundation of experimental studying of cancer (see. Oncology experimental ). Studying of the reasons, mechanisms of development and the wedge, manifestations, is engaged in development of diagnostic methods, prevention and cancer therapy oncology (see).
In the general structure of malignant tumors of R. makes apprx. 90%. The statistical account not in all countries is carried out rather accurately, sometimes it is conducted not over all country in general, and only on certain regions. E.g., in the USA states (Nyo-York, Connecticut, California) can receive data on incidence for the long period only on a nek-eye. In the USSR the obligatory state system of registration of cancer patients is organized (see. Oncological service , Tumours , statistics).
According to Silverberg (1980), in the USA on indicators of incidence and mortality at men cancer of a lung is on the first place, women have a breast cancer.
The analysis of incidence and mortality at R. shows that there are certain features in intensity of distribution of various forms P. over the countries, regions, klimato-geographical zones, ethnic groups. In this regard the great value gets studying of epidemiology of R. Vedutsya of work on drawing up the maps and atlases including data on prevalence of various forms P. depending on structure of soils, level of insolation (ultra-violet activity), the maintenance of nitrozoamin (see Nitrozoamina, a nitrozoamida) in soils, water, food stuffs, etc.
Wide epidemiol. researches allowed to establish that one of the main reasons for increase in cancer cases of a lung at men is smoking, and the risk of emergence of R. increases in proportion to number of the smoked cigarettes, the general duration of smoking, age, in Krom smoking is begun. There are data that smoking increases cancer cases of a lung and at women, though to a lesser extent. It is considered that in the USA in 80 — 85% of cases cancer of a lung is caused by smoking. It is defined that, in addition to R. of a lung, smoking of cigarettes authentically increases cancer cases of a throat and probably influences the frequency of cancer of bladder and mucous membrane of an oral cavity, and also the frequency of cancer of gullet and kidneys.
Thanks to epidemiol. to researches interest in studying of a role of factors of food increased in R.'s etiology of some bodies. Studying of the reasons of decrease in frequency of a carcinoma of the stomach in the USA in recent years in comparison to incidence in Japan showed that emergence of a carcinoma of the stomach is promoted by the food with the high content of carbohydrates, a small amount of protein and insufficient amount of redoxon containing the nitrates applied as preservatives, the use of salty and smoked products. The use of digestible products and absence in food of enough cellulose leads to increase in frequency of cancer of a colon. Also communication between the increased use of fats and frequency of a breast cancer is noted. On the basis epidemiol. data the role of alcohol in increase in cancer cases of a gullet is proved.
As a result of complex researches of epidemiologists and pathologists connection of emergence of some types of R. with inclusion in the period of pregnancy of hormonal drugs was established. Increase in cancer cases of a body of the womb at the women accepting estrogen in the postclimacteric period is noted.
Studying of an etiology of R. is one of the most complex problems of medicine. Experimental and a wedge, oncology saved up considerable actual material and developed perspective approaches to clarification of an etiology of cancer. From the very beginning of R.'s studying at the cellular level numerous hypotheses and theories of an etiology of R., e.g., the embryonal theory, the theory of cellular autonomy were formulated, the theory of a hereditary origin of R. Kazhdaya from them explained an origin (emergence) separate, private, forms P. or some groups of tumors, but any could not be accepted as the uniform, general theory of an etiology of R. V of the 30th of 20 century the opinion began to form that cancer — a concept collective; it is understood as set of various diseases caused numerous etiol, factors. The polyetiological concept of emergence
of R. V of 1936 was created by J. Bittner the so-called factor of milk which appeared a virus of cancer of mammary glands of mice was open (see. Cancer of mammary glands viruses ). Introduction to pilot studies of closed lines lab. animals (see. Inbreeding ) allowed to study in more detail a role of heredity in developing of cancer. Since the beginning of the 50th of 20 century there is a huge interest in an onkovirusologiya. However, first most of researchers considered Oncogenous viruses inf. the agents causing ability to non-regulated and boundless reproduction in cells.
In 1945 L. A. Zilber for the first time pointed to a role of viruses in change of hereditary properties of normal cells on the way of their turning into cancer. By 1960 — 1961 the viruso-genetic theory of emergence of R. developed finally as integration interaction of an oncogenous virus with the cell transformed by it.
In 1964 Mr. of Dulbekko also stated the idea about a role of integration of virus and cellular genomes at a virus carcinogenesis. In 1969 Hübner and Todaro formulated a hypothesis of a virus oncogene (virogen), according to a cut the genome of each normal cell (both somatic, and germinative) contains a genome of an onkovirus of S-type in the integrated form (see. Oncogenous viruses ). It is supposed that the genome of a virogen in a normal cell is completely repressed. but under the influence of various factors (chemical, physical, biological) there can be its expression. As a result of functioning of an expressed virogen products of «cancer proteins» in filial generations of the cell which underwent tumoral transformation can begin. The main hereditarily the fixed qualities of the transformed cells are permanent disturbances of their interaction with surrounding cells and disturbance of regulation of cellular division (see. Cell division ). Isolation of a clone of the transformed cells gives rise to the tumoral growth which takes afterwards kliniko-morphological features of various shape of cancer. So, on the basis of experimental and theoretical representations there was a concept of constant presence of a virogen at any cell, and also the existence of a gene or genes responsible for tumoral transformation of this cell. Such concept based on ideas of participation in formation of tumoral growth of genetic material has more universal character and can be used for an explanation of the most cases which is spontaneously arising R.
Sleduyet to note that still in one of forms of cancer it was not succeeded to find virus particles which with a sufficient share of probability could be regarded in quality etiol, factors in the person. However in such discrete (full) virus particles, apparently, there is no need since tumoral transformation of a cell can happen under the influence of only DNK-provirusa and even smaller elements, such as a gene, an oncogene. Therefore by search etiol, R. agents of the person the main efforts concentrate on detection in normal and tumor cells of fragments of the genetic information coding products of «cancer proteins», i.e. causing a malignancy.
Experimental, clinical and epidemiol. researches demonstrate that various forms P. can develop at people and to be induced at a lab. animals by means of numerous chemical substances, and also under the influence of physical and other impacts. According to the International Agency for Research on Cancer (MAIR), among forms P. with the established etiological agents of 30 — 50% make the forms which are almost definitely caused by environmental factors, and the others in a most part are also connected with the external reasons. It is found out that practically almost all chemical Oncogenous substances (see) are exposed in an organism various, sometimes very difficult, to transformations before they gain specific ability to cause oncogenous effect.
Some Oncogenous factors (see) have not only direct effect on cells of fabrics and bodies, but in some cases on neuroendocrinal bodies, causing hormonal disturbances. The last promote emergence patol, states in fabrics on the basis of which conditions for tumoral transformation of cells and emergence of River are created.
A certain significance in R.'s etiology is attached also to the factors having the expressed immunodepressive effect on an organism. E.g., it is registered that during the use of powerful immunodepressants for the purpose of suppression of reaction of rejection at organ and tissue transplantation, the frequency of tumors (a carcinoma cutaneum, cancer of a neck of uterus) is 10 — 100 times higher, than among the same age group there are population.
Influence of different types of ionizing radiation (see) in experimental conditions depending on a dose through various stage of latency leads to developing of single or multiple tumors, including cancer of mammary glands, went. - kish. path and other bodies. Ultraviolet radiation (see) matters in emergence of a carcinoma cutaneum on the body parts which are treated to his action.
It is established that many of the listed chemical and physical agents possess mutagen action that was justification for the theory of vegetative mutations in quality etiol, concepts of River. According to this concept of R. is the disease caused by certain qualitative changes, or a mutation in genetic material of somatic cells (see. Mutation ).
Most of researchers considers that new growths, including and cancer, represent the general type cellular patol. reactions, edges it can be provoked by various influences. It is much less than followers of the concept of existence of the only causative factor responsible for R.'s emergence
R.'s Emergence is always separated from the moment of action of this or that factor which can be considered as etiological, by so-called stage of latency, during to-rogo completely there are no clinical or other objective signs of tumoral growth. It is supposed that during this period those pathogenetic processes on the basis of which there is a formation of the tumoral growth which is coming to the end with emergence of a certain kliniko-morphological form of cancer (see are developed. Carcinogenesis ).
The structure and classification of cancer
Macroscopically R.'s types are extremely various that is caused by character or type of growth of a tumor, and also features of a structure of fabrics and bodies in which this growth happens. Unlike the benign tumors of the epithelial nature possessing usually expansive (with a pushing off and a prelum of surrounding fabrics) or exophytic (with an eminence over an epithelial cover or a vystilka of hollow body) type of growth, invasive or infiltriruyushchy growth is characteristic of R., at Krom tumoral complexes, groups of cells or separate cells can get infinitely into surrounding fabrics, various layers and zones as initially struck body, and next bodies and fabrics. The tumor grows in lymphatic and blood vessels, its cells are carried on all organism, giving rise to secondary tumoral nodes, or metastasises (see. Innidiation ).
The river, having endophytic growth, extends preferential in the thickness of a wall of hollow body, without acting in its gleam. R. along with the phenomena of an invasion is frequent it is characterized at the same time and — considerably acts as exophytic growth in a gleam of hollow body, napr, throats, a bronchial tube, a stomach, a uterus, a large intestine, a bladder, sometimes getting a hemispherical or fungoid form (see tsvetn, the tab. to St. Stomach , Intestines , fig. 1 and 2; St. Lungs , fig. 14, 15, 16, 17; St. Uterus , fig. 3). At some types of R. by the time of detection of a new growth as a result of discrepancy of level of blood supply and fabric mass of a tumor the expressed secondary changes in a type of dystrophic, necrotic and inflammatory processes develop. It quite often leads to an ulceration of a tumor owing to what it gets a form, e.g., of so-called saucer-shaped cancer (a stomach or a gut). Secondary changes in a cancer tumor can be presented by the centers of hypostasis and sliming (tsvetn, the tab., fig. 1), an arrosion of vessels, disintegration with formation of cysts, zones of fibrosis, scarring with calcification and even an osteogenesis.
Quite often availability of substance or the structures produced by its cells, napr, mucous, muciparous, colloid, mucoid, signet ring cell, pseudomucinous cancer forms the basis for designation of a type of R. All of them usually treat ferruterous R., most often arise in a stomach or a large intestine and differ high intra-or extracellular products of slime. Sometimes such R. loses ferruterous structure, and cells of a tumor or one by one are located with groups in the mucous masses (colloid R.). At intracellular (intracellular) products of slime (signet ring cell R.) the cancer cells overflowed with mucoid substance lie separately in a fibrous stroma. Mucous R. is one of the most malignant forms and is inclined to early innidiation.
Some types of R. have ability to produce various substances or to form the specific structures characteristic of cells and fabrics, with to-rymi they gistogenetichesk are connected. E.g., at a planocellular carcinoma cutaneum the horn substance in the form of so-called cancer pearls produced by epidermis of normal skin is often formed. At the same time the epithelial covers of a number of bodies which normal are not forming horn masses, having undergone tumoral transformation, gain looking alike a multilayer flat epithelium of skin and even begin to produce a keratin. In this regard such forms P., arising in a trachea, bronchial tubes, a stomach, ovaries, name epidermoid R. (tsvetn, the tab., fig. 2, 3, 4). Epidermoid R. of a stomach sometimes is designated the term «cancroid».
An important element from the point of view of morfol, R.'s characteristics along with actually epithelial component, or a parenchyma, tumors is its stromal component. It is usually presented by connecting fabric, vessels and nerves. The quantity and character of this component also finds the reflection in names of forms P. E.g., some forms of adenocarcinomas (which are usually localized in a stomach) are characterized by considerable dominance of a tumoral parenchyma over a stromal component that gives them very soft consistence and similarity by a macroscopic view with tissue of a brain (medullary, or mozgovidny, R.). Other forms P., at low level of development of a stromal component, microscopically differ in a considerable variety of structural options and keep the signs indicating a gistogenetichesky source of tumoral growth that takes place in hepatocellular cancer (tsvetn, the tab. of fig. 5, 6, 7, 8).
Morfol, option P. with the developed stromal component, in Krom epithelial tumoral elements are presented in the form of separate cells or the small separated complexes, call a scirrhus (Greek skirrhos firm) or fibrous R. (tsvetn, the tab., fig. 9, 10, 11).
On the basis gistol, structures, on degree of a deviation from structure of normal fabric allocate highly - the moderate and low-differentiated forms P. Distinguish also not keratosic and more differentiated keratosic planocellular R. Posledny represents gistogenetichesk more mature tumor and contains the layered educations consisting of horn scales.
It is necessary to notice that the terminology used for designation of various forms P. is far from perfect, often irrational, in some cases carries formalnoassotsiativny, and sometimes and eponymous character. The term accepted for designation of ferruterous cancer «adenocarcinoma» (tsvetn. the tab., fig. 12), it is possible to consider one of the most rational since it designates R. which arose from an epithelium of glands and keeping in bigger (the high-differentiated adenocarcinoma) or smaller degree (the low-differentiated adenocarcinoma) structural signs of ferruterous fabric or body. Some details of a structure can be specified terminologically, napr, «the papillary adenocarcinoma» designates ferruterous R. with formation of the papillary growths acting in a gleam of tumoral glands (tsvetn, the tab., fig. 13). In general the term «papillary cancer», or «papillocarcinoma», is quite eurysynusic since the tendency to formation of papillary (papillary) outgrowths is characteristic of R. of many bodies. Especially often such structure has R. of ovaries, a thyroid gland, uterine tubes, a bladder, a large intestine.
The terms «ovsyanokletochny», «small-celled», «macrocellular» or «giant-cell» P. designating various options of undifferentiated cancer of lung (tsvetn, the tab., fig. 14, 15, 16), have formal and associative character and reflect only sizes and a form of cells of a tumor. More accurate and histologically can be considered the justified term for designation of separate forms of cancer of lung, e.g., the term «adenocarcinoma of bronkhioloalveolyarny type» (tsvetn, the tab., fig. 17).
For designation of a carcinoma cutaneum there is an abundance of both the rational, and irrational terms and their synonyms applied quite often to the same new growth. E.g., the terms «cancer of a kangra» and «cancer of Cairo» designate the carcinoma cutaneum arising at the population of some districts of India and Japan in connection with custom to carry under clothes in cold season special ceramic or metal vessels with hot coals or coal dust for heating of a body.
In the nomenclature the number of eponymous terms for designation of separate forms P., napr, «Bowen's cancer» (the carcinoma cutaneum arising against the background of a peculiar dyskeratosis), «Pedzhet's cancer» remains a nek-swarm (a breast cancer from an epithelium of large channels of a nipple).
In the field of the prof. of pathology use the term «professional cancer» for the designation P. arising at workers of separate specialties under the influence of long influence of harmful factors of production or violation of the rules of labor protection and measures of the accident prevention. Carry a carcinoma cutaneum of brushes at radiologists (now practically does not occur), cancer of a bladder at the workers occupied on production of aniline connections, cancer of a lung working some mines (e.g., P, the miners working at extraction of cobalt, nickel, chromium ores with impurity of radioactive materials) to professional R., etc.
In the USSR for specification of volume of defeat at R. the classification providing division of a disease into 4 stages is accepted: the first stage — a tumor of the small sizes without metastasises in regional limf, nodes; the second stage — a tumor of the bigger size, but within the struck body or same, as at the first stage, but with single metastasises in regional limf, nodes; the third stage — a tumor extends to the next bodies and fabrics, there are multiple metastasises in regional limf, nodes; the fourth stage — generalization of tumoral process with distribution on the next bodies, metastasises in regional limf, nodes and the remote bodies.
Was widely adopted also international system of clinical classification of cancer (see). This classification provides definition of prevalence of tumoral process by three criteria — the size of the tumor, existence of metastasises in regional limf, nodes and the remote metastasises. The symbol of T (tumor) designates prevalence of primary tumoral node: T1 — the tumor of the small sizes occupying a part of body; T2 — a tumor of the big sizes, but not going beyond body; T3 — the tumor which is going beyond body and involving the next bodies and fabrics in process; sometimes allocate a stage of T0 (primary tumor is not defined, and there are metastasises) and a stage of TIS for designation of cancer in situ (see Carcinoma in situ). For some localizations on this system the stage of T4 is provided — the tumor goes beyond body, causing destruction of the next bodies. A symbol N (nodulus) designate metastasises in regional limf, nodes: N0 — lack of metastasises, N1 — existence of metastasises. At some localizations of R. depending on group limf, nodes of designation can vary from to N3. The symbol of M (métastasés) designates existence (M3) or lack (M0) of metastasises in the remote bodies and fabrics.
Classification by the TNM system allows to compare the results received by specialists of various countries.
the Main objective of diagnosis of R. is detection of a disease at early stages. Distinguish early and timely diagnosis. Understand recognition of a tumor in a stage of intraepithelial growth when complete elimination of tumoral process is possible as early diagnosis of R. Timely diagnosis of R. is a recognition of process in such stage when the vast majority of patients can be cured (see. Tumours , diagnosis).
Treatment, as a rule, complex, based on use of various methods depending on the nature of a tumor, its localization and a stage of a disease or extent of distribution of tumoral process. It includes operational treatment, chemotherapy, radiation therapy (see Tumours, treatment).
the Forecast is defined by clinical and morphological factors and first of all localization of a tumor. At outside localizations the forecast at timely begun treatment is quite favorable. R.'s localization in internals, and also existence of metastasises in regional limf, nodes and, especially, in the remote bodies considerably worsen the forecast. The initial immune status influences the forecast — at sharp oppression of atrepsy (see atrepsy) the forecast considerably worsens.
Results of treatment are influenced by degree of a differentiation of R.: at the low-differentiated R. usually the forecast is worse.
Rehabilitation of cancer patients
Distinguish medical, professional and social rehabilitation. Medical rehabilitation is directed to strengthening of all fiziol, the processes necessary for development of compensation of the broken functions and is carried out in the course of treatment as soon as the condition of the patient allows. Professional rehabilitation begins during medical rehabilitation and shall come to an end with employment of the patient. In recovery of working capacity social rehabilitation is of great importance, edges consists in correctly picked up types of work. The philosophy of recovery treatment (rehabilitation) is perhaps its earlier beginning and a continuity at all stages (see. Tumours , rehabilitation).
Prevention — see. Tumours , prevention.
Cancer at children
At children, unlike adults, leukoses, tumors of c prevail. N page, malignant lymphoma, tumors of bones, soft tissues, etc. Cancer at children makes, according to various data, 0,8 — 2,0% of all malignant tumors found at children's age. At children cancer of a nasopharynx meets more often, is more rare — cancer of a thyroid gland; papillary ovarian cancer occurs at girls after approach of periods.
Separate cases of a carcinoma of the stomach are described. Messages on a pancreatic cancer at children began to appear.
Features of a clinical picture, diagnosis and treatment — see. Tumours , at children.
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Yu. N. Solovyov, L. E. Denisov.