Clinical characteristics and diagnosis of patients with hereditary nonpolyposis colorectal cancer.

Aim: To study the clinical characteristics of hereditary nonpolyposis colorectal cancer (HNPCC) in the Chinese population and discuss the identification and management of the patients with HNPCC.

Methods: A series of 140 patients with colorectal cancers (CRC) and HNPCC associated tumors from 30 families fulfilling the Amsterdam criteria were analyzed.

Results: A total of 118 patients had CRC. Average age at diagnosis of the first CRC was 45.7 years, 56.8 % and 23.4 % of the first CRC were located proximal to the splenic flexure and in the rectum respectively. Twenty-three (19.5 %) had synchronous and metachronous CRC. Twenty-seven patients were found to have extracolonic tumors. Gastric carcinoma was the most common tumor type in our series (44.4 %).

Conclusion: The frequency of HNPCC was 2.6 % in our series of patients. The main features are an excess of early onset with a propensity to involve the proximal colon, and high frequency of multiple foci. Management and surveillance for these patients should be different from sporadic CRC. Contrary to American and European reports, gastric cancer seems more frequent than endometrial cancer in Chinese. It is necessary to formulate a new HNPCC criterion for Chinese patients.