Etiology and pathology of rectal cancer

By | January 4, 2012

First, the Western cause of cancer has not yet entirely clear, but that the following factors has a close relationship with cancer.
Direct cancer causes 1, dietary factors: high-fat, meat, low-fiber diet and the incidence of colorectal cancer is closely related to high-fat diet will not only stimulate the bile secretion, but also promote intestinal growth of certain anaerobic bacteria, bile alcohols and bile salts upon the formation of anaerobic decomposition of unsaturated cholesterol, such as deoxycholic acid and lithocholic acid in the intestinal tract has increased within the latter two are carcinogenic substances or secondary cancer, it can lead to the occurrence of colorectal cancer .
2 rectal cancer etiology, genetic factors: the family in rectal cancer patients, about 1 / 4 of a family history of cancer, half of which is also a digestive tract tumors. Because the genetic changes in normal cells, cancer patients acquire a body of genetic susceptibility, combined with a motivating factor, so that tissue cell growth, it will develop into cancer, cell genetic mutation, genetic characteristics into a tumor malignant cells, showed the familial cancer.
3 cause of cancer, polyps: risk of colon cancer and polyps are closely related. Some people think that cancer, rectal polyps are precancerous lesions, especially in familial multiple adenomatous polyposis, the possibility of cancerous great; papillary adenomatous polyps, cancer of the opportunity is greater.
4 causes cancer, chronic inflammation: chronic inflammation can lead to rectal cancer. Such as schistosomiasis, amoebic dysentery, chronic non-specific ulcerative colitis, chronic dysentery, etc., can be granuloma, inflammatory pseudo-polyp stage, and cancer. Course of ulcerative colitis in patients over 10 years, easy to evolve, and the high degree of malignant cancer, easy to transfer, the prognosis is poor; to the statistics, colorectal cancer patients, the incidence of colitis colitis patients than those without 8 to 10 times higher.
In addition, the tumor, but also with psychological factors, age, endocrine factors, environmental stress ability, climatic factors, immune disorders and viral infections are closely related, but still need to take place under certain conditions, cancer.
Second, the general classification of rectal cancer
1, early rectal cancer limited to the mucosa and submucosal layer, said layer of early rectal cancer early, usually without lymph node metastasis, but cancer invasion into the submucosal layer, 5% to 10% of the cases had local lymph node metastasis, according to the naked eye Observation of early rectal cancer were divided into 3.
(1) protruded polyps: the appearance of a local uplift of the mucosa can be seen, pedunculated or sessile Rebagliati or present Case 3. This type mostly intramucosal cancer.
(2) flat elevation type: mucosa slightly thick, almost normal, surface processes, or minor uplift, it seems like a coin.
(3) flat elevation with ulcers; such as small coils, edge of the uplift of the central depression. Found only in submucosa cancer.
2, advanced rectal cancer means the cancer tissue invasion in the mucosal layer below until the serosal layer in. Naked eye is divided into three categories.
(1) mass type: The main growth of the cavity, were spherical or hemispherical, the performance of a majority of small ulcers, and easy bleeding. This type of infiltration of small, lymph node metastasis occurs late, the prognosis is good.
(2) ulcerative type: flat since the beginning of the mass, after the central part of necrosis, the formation of large ulcers, edge eversion was butterfly, surface and easy bleeding, infection.
(3) invasive: invasive carcinoma growth mainly along the wall, a marked fibrous tissue reaction caused by intestinal stenosis and obstruction, early lymph node metastasis and poor prognosis.
Three causes cancer, colorectal cancer histological type
Generally divided into adenocarcinoma, mucinous carcinoma and undifferentiated carcinoma.
1, the cancer cells arranged in tubular or alveolar. According to their degree of differentiation, according to Broder divided into ~ grade, that is low grade (well differentiated), malignant secondary (differentiated), high grade (poorly differentiated) and undifferentiated carcinoma. See more of this type.
2, mucous carcinoma cells secrete more mucus, mucus in the extracellular matrix or concentration in the cell nuclear pressed against the edge of mucous cells and more poor prognosis.
3, small cell undifferentiated carcinoma, were round or irregular in shape, were arranged in irregular sheets, infiltration, easy to small vessels and lymphatic invasion, poor prognosis.

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