Abstract

BACKGROUND AND AIMS There are multiple criteria for the clinical diagnosis of hereditary non-polyposis colorectal cancer (HNPCC). The value of several of the newer proposed diagnostic criteria in identifying subjects with mutations in HNPCC associated mismatch repair genes has not been evaluated, and the performance of the different criteria have not been formally compared with one another.

METHODS We classified 70 families with suspected hereditary colorectal cancer (excluding familial adenomatous polyposis) by several existing clinical criteria for HNPCC, including the Amsterdam criteria, the Modified Amsterdam criteria, the Amsterdam II criteria, and the Bethesda criteria. The results of analysis of the mismatch repair genes MSH2and MLH1 by full gene sequencing were available for a proband with colorectal neoplasia in each family. The sensitivity and specificity of each of the clinical criteria for the presence of MSH2 andMLH1 mutations were calculated.

RESULTS Of the 70 families, 28 families fulfilled the Amsterdam criteria, 39 fulfilled the Modified Amsterdam Criteria, 34 fulfilled the Amsterdam II criteria, and 56 fulfilled at least one of the seven Bethesda Guidelines for the identification of HNPCC patients. The sensitivity and specificity of the Amsterdam criteria were 61% (95% CI 43-79) and 67% (95% CI 50-85). The sensitivity of the Modified Amsterdam and Amsterdam II criteria were 72% (95% CI 58-86) and 78% (95% CI 64-92), respectively. Overall, the most sensitive criteria for identifying families with pathogenic mutations were the Bethesda criteria, with a sensitivity of 94% (95% CI 88-100); the specificity of these criteria was 25% (95% CI 14-36). Use of the first three criteria of the Bethesda guidelines only was associated with a sensitivity of 94% and a specificity of 49% (95% CI 34-64).

CONCLUSIONS The Amsterdam criteria for HNPCC are neither sufficiently sensitive nor specific for use as a sole criterion for determining which families should undergo testing for MSH2 and MLH1mutations. The Modified Amsterdam and the Amsterdam II criteria increase sensitivity, but still miss many families with mutations. The most sensitive clinical criteria for identifying subjects with pathogenic MSH2 andMLH1 mutations were the Bethesda Guidelines; a streamlined version of the Bethesda Guidelines may be more specific and easier to use in clinical practice.