Clinical implications of recognition of the hereditary non-polyposis colon cancer syndrome (HNPCC) for the early detection of colorectal cancer.Sb Lek. 1995; 96(3):275-82.SL
Hereditary non-polyposis colon cancer (HNPCC), also known as the Lynch syndrome or, previously, as the cancer family syndrome (CFS) is a recently defined autosomal cancer syndrome which is different from familial adenomatous polyposis and accounts for a considerable proportion of colorectal cancer (CRC). The main features of HNPCC include familial aggregation of CRC (either solely or combined with other, particularly gynaecological cancer sites- Lynch I or II, resp.), very frequent localization of the cancer in the right colon, a considerably lower age at the time of occurrence and a high risk of synchronous and metachronous tumours. Recognition of the syndrome through family history offers an important chance to detect CRC at a presymptomatic stage with a positive effect on the prognosis. In 1981/82 we started a prospective follow-up of symptom-free subjects conforming with the criteria of HNPCC. Up to 1994 we found 364 subjects of this type coming from 38 families. After initial colonoscopy these subjects entered a system of colonoscopic surveillance built up according to the individual degree of risk. Initial colonoscopy revealed cancer in 61 and adenomas in 122 subjects, both in more than 70% in the right colon. The mean age at this time was 47.5 in cancer and 45.3 in adenomas. More cancers and adenomas were found on repeated colonoscopies during surveillance. All the cancers were well resectable, a 5 year survival in all. During this course in a group of 239 non-screened symptomatic cases of the HNPCC syndrome, detected only at the time of colonoscopy, cancer was found in 146 and adenomas in 71 patients. Five year survival was 65% in this group. The cancers in the screened group were Dukes A and B (mostly A) in 82% and C in 18%, in the symptomatic group Dukes A or B (mostly B) in 67%, C in 18 and D in 15%. -
The results show more favourable colonoscopic findings and better prognosis in symptom-free, colonoscopally screened cases of HNPCC than in symptomatic ones and fully justify an active approach based on colonoscopic surveillance of HNPCC subjects prior to diagnosis.