Age-Dependent Performance Of Braf Mutation Testing In Lynch Syndrome Diagnostics

BRAF V600E mutations have been reported as a marker of sporadic microsatellite instability (MSI) colorectal cancer (CRC). Current international diagnostic guidelines recommendBRAFmutation testing in MSI CRC patients to predict low risk of Lynch syndrome (LS). We evaluated the age-specific performance ofBRAFtesting in LS diagnostics. We systematically compared the prevalence ofBRAFmutations in LS-associated CRCs and unselected MSI CRCs in different age groups as available from published studies, databases and population-based patient cohorts. Sensitivity/specificity analysis ofBRAFtesting for exclusion of LS and cost calculations were performed. Among 969 MSI CRCs from LS carriers in the literature and German HNPCC Consortium, 15 (1.6%) harboredBRAFmutations. Six of seven LS patients withBRAF-mutant CRC and reported age were <50 years. Among 339 of 756 (44.8%) of BRAF mutations detected in unselected MSI CRC, only 2 of 339 (0.6%)BRAFmutations were detected in patients BRAFtesting led to high risk of missing LS patients and increased costs at age BRAFtesting in patients BRAFtesting.