Colorectal cancer is a common malignancy, including colon and rectal cancer. The incidence of colorectal cancer from high to low in order for the rectum, sigmoid colon, cecum, ascending colon, descending colon and transverse colon, recent years have a proximal (right semicolon) development trend. It is closely related to lifestyle, heredity and adenoma of colon. The age of onset was aging, with a ratio of 1.65 males to females.
The cause of
The happening of large intestine cancer and tall adipose low cellulose diet, large intestine is chronic inflammation, large intestine adenoma, genetic element and other factor are like: schistosomiasis, pelvic cavity radiates, environmental factor (be short of molybdenum in be like soil), smoke to wait for concerned.
Clinical manifestations of
Colorectal cancer is inchoate without symptom, or the symptom is not apparent, feel unwell only, dyspepsia, defecate occult blood. As cancerous swollen development, the symptom appears gradually, the expression is defecate habit change, bellyacke, hematochezia, abdomen is wrapped piece, intestinal obstruction to wait, companion or not companion is anaemic, calorific wait for systemic symptom with emaciation. Metastasis and invasion of tumor may cause changes in the involved organs. Colorectal cancer has different clinical symptoms and signs depending on its location.
Right colon cancer
The main clinical symptoms of the right colon are loss of appetite, nausea, vomiting, anemia, fatigue and abdominal pain. Right half colonic cancer brings about be short of iron sex anaemia, show fatigue, lack of power, short of breath wait for a symptom. Right half colon because bowel lumen is wide, tumor grows to certain volume just can appear abdominal symptom, this also is tumor when diagnose, one of main reasons with later stage.
Left colon cancer
The left colon is more likely to cause complete or partial ileus than the right. Intestinal obstruction leads to changes in stool habits, including constipation, bloody stool, diarrhea, abdominal pain, abdominal cramps, abdominal distension, etc. Stool with fresh bleeding indicates a tumor at the end of the left semicolon or rectum. The disease is often diagnosed earlier than right colon cancer.
3. Colorectal cancer
The main clinical symptoms of rectal cancer are hematochegia, change of defecation habit and obstruction. Cancerous swollen place is lower, fecal piece is harder person, easy suffer fecal piece attrition causes haemorrhage, it is bright red or dark red more, do not mix with formable excrement and urine or attach at fecal column surface, misdiagnose is "haemorrhoid" haemorrhage. Focal stimulation and mass ulcer secondary infection, constantly causing defecation reflex, easy to be misdiagnosed as "enteritis" or "dysentery." Carcinomatous annular growth, resulting in a narrowing of the intestinal cavity, the early manifestation of fecal column deformation, thinning, late manifestation of incomplete obstruction.
4. Tumor invasion and metastasis
The most common form of invasion in colorectal cancer is local invasion, in which the tumor invades the surrounding tissues or organs, causing corresponding clinical symptoms. Anal incontinence, lower abdomen and lumbosacral persistent pain were caused by rectal cancer invasion and sacral plexus. Tumor cells were implanted and transferred to the abdomen and pelvic cavity to form corresponding symptoms and signs. Rectal examination showed that masses could be detected in the fossa of the bladder and rectum or the fossa of the uterus and rectum. Tumor was widely implanted and transferred in the abdomen and pelvic cavity to form peritoneal effusion. There are two main ways of distant metastasis of colorectal cancer: lymphatic metastasis and hematogenous metastasis. Tumor cells can be transferred to lymph nodes through lymphatic vessels, or to liver, lung and bone through hematogenous metastasis.