Phenotype and management of patients with familial adenomatous polyposis in Hong Kong: perspective of the Hereditary Gastrointestinal Cancer Registry.

OBJECTIVES To report on the phenotypic spectrum and clinical management of Chinese patients suffering from the rare autosomal dominant colorectal cancer syndrome of familial adenomatous polyposis. DESIGN Analysis of prospectively collected data from the database of a regional registry. SETTING The Hereditary Gastrointestinal Cancer Registry, Hong Kong. PARTICIPANTS One hundred and eight patients with proven familial adenomatous polyposis from 36 local Chinese families with the condition recruited to the Registry from 1995 to 2001. INTERVENTIONS Screening programme for at-risk family members, prophylactic surgery at presymptomatic diagnosis, and surveillance programme for extracolonic lesions in affected individuals. MAIN OUTCOME MEASURES Rate of colorectal cancer, type of surgical treatment, spectrum of extracolonic lesions, and management of the syndrome. RESULTS Fifty patients suffered from colorectal cancer with a mortality rate of 78.0%. The strategy of presymptomatic diagnosis by screening and appropriate prophylactic surgery reduced the incidence of colorectal cancer. Affected individuals were prone to develop potentially serious extracolonic lesions including thyroid cancer (5.7%), desmoid tumour (15.7%), gastroduodenal adenomas (7.1%), duodenal microadenoma (17.1%), and pouch polyposis (17.4%). CONCLUSIONS Screening and prophylactic surgery are effective ways to prevent colorectal cancer for patients with familial adenomatous polyposis. Lifelong regular surveillance is necessary to detect and manage extracolonic lesions. A dedicated registry is essential to coordinate clinical management and to compile data for furthering knowledge of this rare but complex syndrome.