SCREENING FOR HEREDITARY NONPOLYPOSIS COLORECTAL-CANCER IN NEW-ZEALAND

Objective: To study the incidence of neoplasia in at-risk members of families affected by hereditary non-polyposis colorectal cancer (HNPCC). Design: At-risk members of families affected by HNPCC were invited to participate in a prospective colonoscopic screening programme. Setting: The study was coordinated by a registry based in the Pathology Department of the University of Auckland School of Medicine. Participants underwent colonoscopy in public and private hospitals throughout New Zealand. Participants: Seventy-two volunteers from eight families in which all criteria for HNPCC were met (group A) and 28 came from eight families in which some criteria were met (group B). There were 51 men and 49 women with a mean age of 34 years. All were first degree relatives of family members with bowel cancer. Main outcome measures: The groups yielded a total of 25 adenomas and two adenocarcinomas, the latter occurring in a 29 year-old man and a 36-year-old woman. Adenomas in group A patients were more likely to include a villous component and to show high grade dysplasia. Conclusions: The findings support the need for a properly coordinated screening programme and indicate the involvement of the adenoma in the evolution of HNPCC. The enhanced aggression of adenomas in HNPCC justifies short interval follow-up.