Clinical evidence for the adenoma-carcinoma sequence, and the management of patients with colorectal adenomas.

A large body of clinical evidence supports the belief that over 95% of colorectal cancers arise in benign adenomatous polyps that develop and grow very slowly over many years. Interruption of the adenoma-carcinoma sequence by resecting adenomatous polyps is a powerful method of secondary prevention of colorectal cancer. Colonoscopy is the procedure of choice for the diagnosis and resection of colorectal polyps. Patients who have had colonoscopic resection of adenomas, and in some cases their close relatives, are at increased risk for developing metachronous polyps and cancer and may benefit from follow-up colonoscopic surveillance. This surveillance should be individually tailored to the perceived risk of each case depending on the features of the adenomas removed and other patient factors such as family history. Widespread adoption of current postpolypectomy guideline recommendations is protective and conserves medical resources.