Colorectal cancer is a common malignant tumor, including colon cancer and rectal cancer. The incidence rate of colorectal cancer from high to low is rectum, sigmoid colon, cecum, ascending colon, descending colon and transverse colon, and in recent years, there is a tendency to develop to the proximal end (right hemicolectomy). The age of onset tends to be older, and the ratio of men to women is 1.65:1.
Causes
1.Irregular diet structure (20%).
The etiology of intestinal cancer is related to unreasonable dietary structure, too much fatty, sweet, high-calorie and low-fiber food, which also hinders the peristalsis of intestine and stomach and promotes the accumulation and absorption of toxins, causing the high incidence of intestinal cancer.
2. Chronic inflammation of the colon (30%).
After a statistical survey, it was found that the risk of the disease occurring in chronic ulcerative colitis is about ten times higher than normal, and the risk of sudden malignancy in bleeding ulcerative colitis is even greater.
3.Environmental factors (10%).
Environmental changes also tend to cause the emergence of intestinal cancer, with the increasing modernization and industrialization of life, room renovation, exhaust pollution, pesticide abuse and other factors that lead to the reduction of our immune system, also belong to the common causes of intestinal cancer.
4.Heredity (15%).
Heredity is also the main cause of intestinal cancer. 25% of bowel cancer occurs in families with a history of bowel cancer. The incidence of bowel cancer is also 25% if some family members are prone to grow polyps and let them develop, and elderly people over 50 years old should take various measures to prevent bowel cancer. Because, 50% of the elderly over 60 years old will have large intestinal polyps, and we do not know which of these polyps of different sizes will develop into intestinal cancer.
5.Other factors such as: schistosomiasis, pelvic radiation, environmental factors (such as lack of molybdenum in soil), smoking, etc. are related.
Clinical manifestations
Colorectal cancer has no symptoms in the early stage, or the symptoms are not obvious, only discomfort, indigestion, fecal occult blood, etc. With the development of cancer, symptoms will gradually appear, which are manifested as change of stool habit, abdominal pain, blood in stool, abdominal mass, intestinal obstruction, etc., with or without systemic symptoms such as anemia, fever and emaciation. Tumor may cause changes in affected organs due to metastasis and infiltration. Colorectal cancer shows different clinical symptoms and signs due to different parts of its development.
1.Right hemi-colon cancer
The main clinical symptoms of right hemicolectomy are loss of appetite, nausea, vomiting, anemia, fatigue and abdominal pain. Right hemicolectomy leads to iron deficiency anemia, which shows fatigue, weakness, shortness of breath and other symptoms. Because of the wide intestinal cavity, abdominal symptoms will appear only when the tumor grows to a certain volume, which is one of the main reasons for the late stage when the tumor is diagnosed.
2.Left colon cancer
The lumen of left hemicolectomy is narrower than the lumen of right hemicolectomy, so left hemicolectomy is more likely to cause complete or partial intestinal obstruction. Intestinal obstruction leads to change of stool habit, constipation, blood in stool, diarrhea, abdominal pain, abdominal cramps and bloating. Fresh bleeding stools indicate that the tumor is located in the left hemicolectomy or rectum. The diagnosis of the disease stage is often earlier than that of right hemicolectomy.
3.Rectal cancer
The main clinical symptoms of rectal cancer are blood in stool, change of bowel habit and obstruction. If the cancer site is low and the fecal mass is hard, the bleeding is easily caused by the friction of the fecal mass, mostly bright red or dark red, not mixed with formed feces or attached to the surface of the fecal column, which is misdiagnosed as “hemorrhoid” bleeding. The secondary infection caused by lesion stimulation and mass ulceration constantly causes defecation reflex, which is easily misdiagnosed as “enteritis” or “bacillary dysentery”. If the cancer grows in a circular pattern, it leads to narrowing of intestinal lumen, which is manifested as deformation and thinning of fecal column in early stage and incomplete obstruction in late stage.
4.Tumor infiltration and metastasis
The most common form of infiltration of colorectal cancer is local invasion, and the tumor invades the surrounding tissues or organs, causing the corresponding clinical symptoms. Anal incontinence, persistent pain in lower abdomen and lumbosacral region are caused by rectal cancer invading sacral plexus. Tumor cell implantation and metastasis to the abdominopelvic cavity will form corresponding symptoms and signs. Rectal finger examination can find masses in the cysto-rectal fossa or utero-rectal fossa, and tumor implantation and metastasis in the abdominopelvic cavity extensively will form peritoneal fluid. There are two main ways of distant metastasis of colorectal cancer: lymphatic metastasis and hematogenous metastasis. Tumor cells metastasize to lymph nodes through lymphatic vessels, and also to liver, lung, bone and other parts through bloodstream metastasis.
Examination
1.Laboratory examination
Laboratory tests such as routine blood, complete biochemistry (liver and kidney function + serum iron), routine stool + fecal occult blood, etc. can help to understand whether the patient has iron deficiency anemia, liver and kidney function and other basic conditions. Blood tumor marker carcinoembryonic antigen (CEA) test is performed to help the diagnosis of tumor. In patients with colorectal cancer, high CEA level does not mean that all of them have distant metastasis; there are a few patients with metastases, CEA is not increased.
2.Endoscopy
Colonoscopy is to extend a fiberoptic colonoscope into the ileocecal region at the beginning of the colon to examine the colon and rectal cavity, and to perform biopsy and treatment during the examination. Colonoscopy is more accurate than barium enema X-rays, especially for small colon polyps, which are removed by colonoscopy and confirmed pathologically. Removal of benign polyps can prevent their transformation into colorectal cancer, and cancerous polyps can help clarify the diagnosis and treatment.
3.Biopsy biopsy is of decisive significance in confirming the diagnosis of colorectal cancer, especially early cancer and polyp cancer, as well as differential diagnosis of lesions, which can clarify the nature, histological type and malignancy of tumor, judge the prognosis and guide clinical treatment.
Treatment
Treatment of patients needs to be moderate, neither over-treatment nor under-treatment. It can be seen clinically that patients die not because of cancer itself, but due to unscientific and inappropriate treatment. The more important treatment for advanced cancer is to reduce pain, improve quality of life, control the disease, and “seek progress in stability” in order to obtain “long-term survival with tumor”.
1.Surgical treatment
2.Chemotherapy
3.Radiation therapy
Prevention
1.Eating more high-fiber food
It has been noticed early that high fiber diet can reduce the prevalence of colon cancer. Studies have found that daily intake of more than 35g of fiber can reduce the incidence of colon cancer by 40%. The incidence of rectal cancer in black African residents is very low, and scholars have found that this is closely related to the fact that they mainly eat foods rich in fiber, such as corn and vegetables. Further research found that the lack of fiber in food can reduce the amount of stool and slow down intestinal peristalsis, so the concentration of carcinogenic substances in the intestine increases, and the time for carcinogens to act with the mucous membrane of the intestinal wall is prolonged, and then colon tumors are prone to occur in the usual diet, and we should try to consume more vegetables, fruits and fiber and eat reasonably to reduce the occurrence of colon cancer.
Some studies have shown that supplementation with vitamins a, c, and e can convert the overgrowth of colonic epithelium in adenoma patients to normal, but the current information does not support the use of antioxidant vitamins to prevent colorectal cancer. Dietary thioether contained in garlic, onions, leeks, and shallots; terpenes contained in citrus; phytol contained in grapes, strawberries, and apples, as well as carrots, diosgenes, and carotenoids contained in watermelon, are thought to inhibit mutations and have anti-cancer effects. Garlic, in particular, has been shown to be the vegetable with the strongest protective effect against distal colon cancer.
2.Supplement vitamin D and calcium
Calcium supplementation can not only improve osteoporosis, but also prevent the occurrence of intestinal cancer. This conclusion is not an empty wind, researchers at Sloan-Kettering Cancer Center in New York have investigated people at high risk of colon and rectal cancer and found that conscious dietary calcium supplementation for 2 to 3 months slows down intestinal cell division and reduces the occurrence of intestinal cancer.
3.Incorporate more folic acid-rich food
Folic acid is one of the b vitamins. Epidemiology, animal experiments and clinical data all suggest that increasing the intake of folic acid in daily diet and improving serum folic acid level can reduce the incidence of intestinal cancer. Foods rich in folic acid: animal liver and kidney, eggs, beans, yeast, green leafy vegetables, fruits and nuts.
As mentioned above, we can all prevent bowel cancer by eating a light diet, not overeating, eating regularly, and not working under too much pressure.