Oncogenetic Testing for Lynch Syndrome and Familial Adenomatous Polyposis

This is a clinical practice guideline for patients with colorectal cancer or for patients who are otherwise at risk of Lynch syndrome or familial adenomatous polyposis (FAP). The guideline provides recommendations on the identification and referral of patients to genetic centres for counselling, and discusses appropriate follow-up screening for Lynch syndrome and FAP. The use of Microsatellite instability (MSI) as both a predictor of treatment effectiveness and a predictor of Lynch syndrome is reviewed, with MSI compared to immunohistochemistry when screening for Lynch syndrome.