Suspected HNPCC and Amsterdam criteria II: evaluation of mutation detection rate, an international collaborative study.

BACKGROUND AND AIMS: The Korean Hereditary Tumor Registry has proposed criteria for suspected hereditary nonpolyposis colorectal cancer (S-HNPCC criteria I and II) and confirmed their validity in an international collaborative study. The S-HNPCC criteria included families that did not fulfill the Amsterdam criteria, but in whom HNPCC was nevertheless strongly suspected. The S-HNPCC criteria was also revised accordingly since some S-HNPCC families now fullfil the revised Amsterdam criteria. The original Amsterdam criteria have recently been revised, including some extracolonic cancers. This study compared the mutation detection rates between the revised and previous Amsterdam and S-HNPCC criteria. PATIENTS AND METHODS: Data on the mutational status of 393 HNPCC suspected families were collected from ten different institutes. Two hundred families were categorized into old S-HNPCC criteria (142 into criteria I and 58 into criteria II) and 193 families into Amsterdam criteria I.
RESULTS: Of the 142 old S-HNPCC criteria I families 24 fulfilled the Amsterdam criteria II as the data were reclassified according to the revised criteria, increasing the proportion of the families fulfilling the Amsterdam criteria by 12.4%. The mutation detection rate of the revised criteria was very little changed compared to the old criteria; 26% and 27% in the S-HNPCC criteria, and 50% and 52% in the Amsterdam criteria.
CONCLUSION: The mutation detection rate is hardly affected by the revision of the Amsterdam criteria although the population of patients fulfilling the criteria is increased. The value of revised S-HNPCC criteria is equivalent to that of as the old S-HNPCC criteria in selecting of candidate patients for genetic testing.