[Necessity and feasibility of screening for colorectal cancer in China].

Incidence and mortality of colorectal cancer has increased significantly in recent years. Screening for colorectal cancer is the most effective method to decrease mortality. Colorectal adenoma is the precancerous lesion of colorectal cancer and can be detected through colonoscopy, which is the crucial in the early diagnosis and early treatment for colorectal cancer. The first step of screening is the selection of target population and the second step is colorectal examination. The selection of candidate for screening has direct effect on the efficacy of screening. The methods in common use include fecal occult blood test, questionnaire for high risk factors of colorectal cancer, colonoscopy, sigmoidoscopy, and CT virtual colonoscopy. Among those, colonoscopy is the most reliable method and widely used in the screening for colorectal cancer.