Abstract
The author outlines clinical features of the colorectal cancers associated with hereditary non-polyposis colorectal cancer （HNPCC）. These features include the early age of onset, high frequency of multiple colorectal cancers and right-side colon cancer, relatively good prognosis and the probability of the patient’s poor response to anti-cancer drugs. With regard to surgical treatment, the potential benefit of preventive colectomy before onset or removal of a large part of colon during surgery for colorectal cancers has not been clarified yet. For prevention, persons with HNPCC should follow generally recommended lifestyle which decreases the risk of colorectal cancers based on evidence from epidemiological studies. To date, effective drugs for chemoprevention have not yet been identified. Annual screening colonoscopy is desirable for early detection of colorectal cancers in persons with HNPCC.
