ACG Clinical Guideline: Diagnosis and Management of Adenomatous Colorectal Polyposis Syndromes

APC

Monoallelic germline pathogenic variants in APC (familial adenomatous polyposis) or biallelic variants in MUTYH (MUTYH-associated polyposis), driving cumulative risk of colorectal, duodenal, ampullary and gastric cancer.

The American College of Gastroenterology has updated its guideline on hereditary adenomatous colorectal polyposis syndromes, developed using the GRADE methodology. The document covers selection of individuals for risk assessment, modality and timing of germline genetic testing, cancer risk mitigation through endoscopic and surgical intervention, and the role of chemoprevention. It sets out management for patients with phenotypic colorectal polyposis according to genetic test results — or in their absence — and addresses presymptomatic diagnosis in families with a known familial pathogenic variant. Colorectal and extracolonic benign and malignant manifestations are reviewed with a focus on the two most common syndromes: familial adenomatous polyposis (APC) and MUTYH-associated polyposis.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

The value of such a document is not novelty — it generates no new data — but the explicit account of what has changed since the previous version, particularly surgical timing and duodenal surveillance, where practice varied between centres. Two points matter in clinic: the recommendation to test on a polyposis phenotype irrespective of family history, and the management pathway explicitly provided when testing is negative, a common situation that had been poorly codified. The document remains centred on APC and MUTYH, whereas polyposes attributable to NTHL1, MSH3 or POLE/POLD1 now fall within a broader genome-wide analysis.

Analysis by Dr Thibaut Benquey