To Screen or Not To Screen for Lynch Syndrome

Abstract

rosatellite instability (MSI) test. Patients with an abnormal screen can then have a diagnostic DNA test for mismatch repair mutations to confi rm or rule out Lynch syndrome. Family history is the basis for two different sets of criteria to determine which patients should be considered at risk for Lynch syndrome: the Amsterdam criteria and the Bethesda guidelines. But family history isn’t always available, and many patients are thus missed, along with the opportunity to identify their at-risk relatives. That’s why the federal Centers for Disease Control and Prevention (CDC) convened its independent panel — the Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group — to consider a broader screening strategy. The working group released its fi ndings in January 2009. According to the CDC website, the group “found good scientifi c evidence to recommend that all individuals with a new diagnosis of colorectal cancer (regardless of age or family history) be offered genetic testing for Lynch syndrome, in order to help prevent cancer in their close relatives.” It did not fi nd enough evidence to recommend any specifi c preliminary screening strategy, e.g., MSI versus IHC.