Here we discuss the major mistakes that are made when gastroenterologists deal with CRC diagnosis, prevention and treatment, and how to avoid them. The list of mistakes and the discussion that follows is evidence based and integrated with our longstanding clinical experience.
Mistake 1 | Failing to test for hereditary CRC syndromes in CRC patients who have no family history of the disease
Lynch syndrome, an autosomal dominant disorder caused by germline mutations in DNA mismatch repair (MMR) genes (i.e. MSH2, MLH1, MSH6 and PMS2), is the most common form of hereditary CRC, accounting for 1–3% of all tumours.1 Familial adenomatous polyposis (FAP), another autosomal dominant disease caused by germline mutations in the APC gene, is the most frequent polyposis syndrome.4Although a positive family history of Lynch syndrome or FAP must prompt them to be ruled them out in any at-risk relative, it is important to be aware that de novo cases occur in a significant proportion of patients, especially cases of FAP.5 Therefore, it is highly recommended that universal tumour MMR testing—by immunohistochemistry and/or microsatellite instability testing—be performed in any patient diagnosed with CRC to exclude Lynch syndrome, regardless of family history.6 Testing for germline mutations in the APC or MUTYH genes should be considered in those diagnosed with multiple (i.e. >10) cumulative adenomatous polyps.1,7