Prognosis of hereditary nonpolyposis colorectal cancer (HNPCC) and the role of Japanese criteria for HNPCC.

In 1991, the Japan Research Society for Cancer of the Colon and Rectum proposed clinical criteria (Japanese criteria) for hereditary nonpolyposis colorectal cancer (HNPCC). According to the Japanese and Amsterdam criteria, three groups of patients are defined: 1) those diagnosed as having HNPCC using the Amsterdam criteria (Amsterdam HNPCC); 2) those classified as Japanese criteria category A (putative HNPCC-A) and 3) those classified as Japanese criteria category B (putative HNPCC-B). In order to evaluate the prognosis of HNPCC and the role of the Japanese criteria, the clinicopathological characteristics, recurrence and survival rates of Amsterdam HNPCC (n 14) and putative HNPCC-A (n 31) and B (n 100) patients were studied, and compared with those of patients with sporadic colorectal cancer (controls, n 1604). The Amsterdam clinicopathological characteristics and those of putative HNPCC were the same as those reported previously. Neither local nor distant recurrences were observed in the Amsterdam HNPCC and putative HNPCC-A during a median follow-up period of 137 months. The 5-year survival rates of the Amsterdam HNPCC, putative HNPCC-A, B, and control patients were 92.3%, 81.2%, 66.5% and 60.0%, respectively, and those of the former two groups were significantly better than those of the others (P<0.05). These results show that the prognosis of HNPCC is better than that of sporadic colorectal cancer, and that the Japanese criteria, especially for category A, can be used to select putative HNPCC patients from among those with sporadic colorectal cancers.