CLINICAL IMPACT OF COLONOSCOPIC SCREENING IN FIRST-DEGREE RELATIVES OF PATIENTS WITH HEREDITARY NONPOLYPOSIS COLORECTAL-CANCER

Sixty-one asymptomatic individuals with an affected first-degree relat ive from five large hereditary non-polyposis colorectal cancer (HNPCC) kindreds were screened by colonoscopy. Neoplasms were found in nine ( 15 per cent) of 61 individuals on the first screen. Five subjects had a single adenoma while two had two adenomas each. There were two patie nts (3 per cent) with malignant neoplasms: one with a Dukes B adenocar cinoma and one with synchronous Dukes C adenocarcinomas in the caecum and ascending colon. These findings support the hypothesis that adenom as do not occur in large numbers in HNPCC families but, because of the high malignant conversion rate, biennial colonoscopy with removal of polyps seen is recommended.