Impact of universal immunohistochemistry on Lynch syndrome diagnosis in an Australian colorectal cancer cohort

Abstract

Background: Current guidelines recommend a step-wise screening algorithm for all colorectal carcinomas (CRC) to identify patients with Lynch syndrome (LS). Aim: To describe the frequencies of mismatch repair deficiency (dMMR), BRAFV600E mutations and MLH1 methylation in resected CRC, and evaluate the impact of universal screening on LS detection. Methods: Retrospectively, 1171 consecutive cases of resected CRC were identified between 2010 and 2017 from a large multi-centre pathology service. Testing for dMMR by immunohistochemistry (IHC) was initiated by the reporting pathologist from 2010, until universal testing was introduced in 2015. Patients with dMMR were referred to the Family Cancer ..