A Review on Colorectal Cancer

摘要

Cancers of the colon and rectum are the second leading cause of cancer death. Fifty percent of the colorectal cancer occurs in either the lower (sigmoid) colon or the rectum and should be easy to detect at an early stage. The majority of the colon cancers are not inherited, but rather are considered sporadic, having developed from an accumulation of mutations throughout the course of a lifetime. The epidemiological risk factors for cancers, other than genetic risk factors, include dietary components, such as the amount of fat and fiber in the diet, intake of calcium, vitamins of the antioxidant class, NSAIDS such as aspirin and specific inhibitors of cyclo-oxygenase. The risk of colon cancer increases with age, the history of previous polyps or cancer, family history of cancer, history of long standing inflammatory bowel disease including ulcerative colitis and Crohn’s disease. Colonoscopy plays an important role in the medical care of patients with colorectal cancer. It is generally used for both the diagnosis of different stages of colorectal cancer and the treatment of early colorectal cancers and its precursors.