Colon cancer – defeat of various departments of a large intestine (blind, obodochny, sigmovidny, a rectum) the malignant tumor proceeding from an epithelium of an intestinal wall. The symptomatology at a colon cancer includes abdominal pains, a meteorizm, intestinal frustration, violation of intestinal passability, pathological impurity in kalovy masses, weakness, an iskhudaniye. The colon cancer can be defined at a stomach palpation; for the confirming diagnostics the kolonoskopiya with a biopsy, an ultrasonografiya, an irrigoskopiya, KT, nuclear magnetic resonance, PET is carried out. Radical methods of cancer therapy of a thick gut are one-stage or stage-by-stage rezektsionny interventions.
Colon cancer (colorectal cancer) – the malignant new growth developing from an epitelialny vystilka of a wall of a large intestine. The statistics on cancer cases of a thick gut is unfavourable: annually in the world over 500 thousand new cases of a colorectal cancer come to light, and the most part from them is the share of industrially developed countries - the USA, Canada, countries of Western Europe, Russia. In structure of a female oncopathology the colon cancer takes the 2nd place after a breast cancer, and at men on frequency concedes only to a prostate cancer and cancer of a lung. The majority of cases of a colorectal cancer are the share of persons 50 years are more senior; men are ill 1,5 times more often than women. A disturbing factor is late detectability: the colon cancer is found in 60-70% of patients at the III-IV stage.
Reasons of a colon cancer
Long-term studying and the analysis of a problem allowed to call the most significant etiologichesky factors promoting increase in risk of development of a colon cancer, are heredo-familial and alimentary factors, and also precancer diseases. Among genetically determined reasons the greatest value has family polyposes which practically in 100% of cases leads to development of a colon cancer. Besides, patients with Lynch's syndrome have the increased risk of development of a colorectal cancer - in this case tumoral defeat usually develops at persons more young than 45 years and is localized in the right departments of an obodochny gut.
Investigating dependence of frequency of a colon cancer on character of food and a way of life, it is possible to note that developing of an oncopathology is promoted by prevalence in food in a diet of animal protein, fats and the refined carbohydrates at deficiency of vegetable cellulose; obesity and metabolic violations, gipokineziya. Mutagen and cancerogenic action on cages of an intestinal epithelium various chemical compounds possess (the aromatic hydrocarbons and amines, nitroconnections derivative of tryptophane and a tirozin, steroid hormones and their metabolites, etc.)
The probability of a colorectal cancer progressively increases in conditions of chronic locks, a long experience of smoking, chronic diseases of intestines. In particular, in coloproctology are carried to precancer diseases: chronic colitis (NYaK, a disease Krone), a divertikulyarny disease of a large intestine, single polyps of a thick gut (adenomatozny and fleecy polyps with a diameter more than 2 cm ozlokachestvlyatsya in 45-50% of cases).
Classification of a colon cancer
The malignant tumor can arise in various anatomic departments of a large intestine, however the frequency of their defeat is not identical. The prevailing localization is the descending obodochny and sigmovidny gut (36%); further the blind and ascending obodochny gut (27%), a rectum and the anal channel (19%), a cross obodochny gut (10%), etc. follows.
On the nature of growth of a tumor of a thick gut are subdivided on ekzofitny (the guts growing in a gleam), endofitny (extending in thickness of an intestinal wall) and mixed (the tumors ulcers combining ekzo-and an endofitny form of growth). Taking into account a histologic structure cancer of an obodochny gut can be presented by an adenocarcinoma of various level of a differentiation (more than 80%), a mucous adenocarcinoma (mukoidny cancer), mukotsellyulyarny (perstnevidnokletochny) cancer, the undifferentiated and not classified cancer; cancer of a rectum and the anal channel in addition – planocellular, bazalnokletochny and ferruterous and planocellular cancer.
According to the international TNM system, on the basis of criteria of depth of an invasion of primary tumor, the regionarny and remote metastasis, allocate stages:
- – given for assessment of primary tumor it is not enough
- Tis – decides a tumor on the intraepitelialny growth or an invasion of a mucous membrane
- T1 – infiltration by a tumor of a mucous and submucous layer of a thick gut
- T2 – infiltration by a tumor of a muscular layer of a thick gut; mobility of an intestinal wall is not limited
- T3 – germination by a tumor of all layers of an intestinal wall
- T4 – germination by a tumor of a serous cover or distribution on the next anatomic educations.
Taking into account existence or lack of metastasises in regionarny lymph nodes distinguish the following degrees of a colon cancer: N0 (lymph nodes are not affected), N1 (metastasises it is struck from 1 to 3 lymph nodes), N2 (metastasises affected 4 and more lymph nodes). Lack of the remote metastasises is designated by a M0 symbol; their existence - M1. Metastasis of a colon cancer can be carried out in the limfogenny way (in regionarny lymph nodes), a hematogenic way (in a liver, bones, lungs, etc.) and an implantation/contact way with development of a kartsinomatoz of a peritoneum and cancer ascites.
Symptoms of a colon cancer
Clinical symptoms of a colon cancer are presented by 5 leading syndromes: painful, intestinal disorders, violation of intestinal passability, pathological allocations, deterioration in the general condition of patients. Abdominal pains are the earliest and constant symptom of a colon cancer. Depending on localization of a tumor and a stage of malignant process they can be various on character and intensity. Patients can characterize the belly-aches as pressing, aching, skhvatkoobrazny. At the expressed morbidity in the right podreberye it is necessary to exclude cholecystitis and stomach ulcer of a 12-perstny gut at the patient; in case of localization of pain in the right podvzdoshny area the differential diagnosis is carried out with an acute appendicitis.
Already in initial stages of a colon cancer the symptoms of intestinal discomfort including an eructation, nausea, vomiting, appetite loss, heavy feeling and overflow of a stomach are noted. At the same time the intestinal frustration demonstrating violation of motility of intestines and a passage of intestinal contents develop: diarrhea, locks (or their alternation), abdominal murmur, meteorizm. At ekzofitno the growing colon cancer (most often left-side localization) finally partial or full obturatsionny intestinal impassability can develop.
Emergence in excrements of pathological impurity can demonstrate development of cancer of disteel departments sigmovidny and a rectum (blood, slime, pus). Plentiful intestinal bleedings arise seldom, however long blood loss leads to development of chronic post-hemorrhagic anemia. Violation of the general health at a colon cancer is connected with intoxication caused by disintegration of a cancer tumor and stagnation of intestinal contents. Patients usually complain of an indisposition, fatigue, subfebrilitt, weakness, an iskhudaniye. Sometimes existence palpatorno of the defined education in a stomach becomes the first symptom of a colon cancer.
Depending on a clinical current allocate the following forms of a colon cancer:
- toksiko-anemichesky – in clinic the general symptoms (fever, the progressing gipokhromny anemia) prevail.
- enterokolitichesky – the main manifestations are connected with intestinal frustration that demands differentiation of a colon cancer with enteritis, colitis, enterokolity, dysentery.
- dispepsichesky – the simptomokompleks is presented by the gastrointestinal discomfort reminding clinic of gastritis, stomach ulcer of a stomach, cholecystitis.
- obturatsionny – is followed by the progressing intestinal impassability.
- pseudo-inflammatory – it is characterized by signs of the inflammatory process in an abdominal cavity proceeding with temperature increase, abdominal pains, leykotsitozy and so forth. This form of a colon cancer can mask under adneksit, appendicular infiltrate, pyelonephritis.
- atypical (tumoral) – the tumor in an abdominal cavity comes to light palpatorno against the background of visible clinical wellbeing.
Diagnosis of a colon cancer
Purposeful diagnostic search includes clinical, radiological, endoscopic and laboratory inspection. Valuable data can be received at objective survey, a palpation of a stomach, percussion of an abdominal cavity, a manual research of a rectum, a gynecologic research.
Radiological diagnostics includes a survey X-ray analysis of an abdominal cavity, an irrigoskopiya with use of contrast substance. For the purpose of visualization of a tumor, capture of a biopsy and dabs for a cytologic and histologic research the rektosigmoskopiya and a kolonoskopiya is carried out. The ultrasonografiya of a large intestine, a positron and issue tomography belong to number of informative methods of topichesky diagnostics. Laboratory diagnosis of a colon cancer assumes a research of the general blood test, a calla on the hidden blood, definition of the cancer and embryonic anti-gene (CEAG). For the purpose of assessment of prevalence of malignant process ultrasonography of a liver, MSKT of an abdominal cavity, ultrasonography of a small pelvis, a thorax X-ray analysis, according to indications - a diagnostic laparoscopy or an eksplorativny laparotomy is carried out.
The colon cancer demands differentiation with many diseases of the intestines and bodies, adjacent to it, first of all, - chronic colitis, nonspecific ulcer colitis, a disease Krone, actinomycosis and tuberculosis of a thick gut, benign tumors of a thick gut, polipozy, divertikulity, cysts and tumors of ovaries.
Cancer therapy of a thick gut
The radical way of cancer therapy of a thick gut assumes carrying out rezektsionny interventions on obodochny, sigmovidny or a rectum. The nature of operation and volume of a resection depends on localization and prevalence of a tumoral invasion. At a colon cancer performing both the one-stage, and stage-by-stage surgeries including a resection of a gut and imposing of a kolostoma with the subsequent reconstructive operation and closing of an intestinal stoma is possible. So, at defeat the blind person and the ascending department of an obodochny gut the right-hand gemikolektomiya is shown; at cancer cross guts - its resection, at a tumor of the descending department - a left-side gemikolektomiya, at cancer of a sigmovidny gut – a sigmoidektomiya.
The surgical stage of cancer therapy of a thick gut is supplemented with postoperative chemotherapy. In the started inoperable cases palliative operation (imposing of a roundabout intestinal anastomoz or intestinal stoma), chemotherapeutic and symptomatic treatment is made.
Forecast and prevention of a colon cancer
The forecast of a colon cancer depends on a stage at which tumoral process was diagnosed. At detection of an oncopathology at T1 stage the remote results of treatment satisfactory, 5-year survival makes 90-100%; at T2 stage – 70%, T3N1-2 – about 30%. Prevention of a colon cancer assumes dispensary observation of risk groups, treatment of precancer and background diseases, normalization of food and way of life, carrying out screening researches (a calla on the hidden blood and kolonoskopiya) to persons 50 years are more senior. The patients operated concerning a colorectal cancer for timely diagnostics of a recurrence of cancer of large intestine in the first year each 3 months have to undergo the inspection at the proctologist including a manual research of a rectum, a rektoromanoskopiya columned or an irrigoskopiya.