Hidden Metachronous Invasive Rectal Cancer after Repeated Endoscopic Treatment Following Ileorectal Anastomosis for Familial Adenomatous Polyposis: A Case Report

Introduction

Patients with familial adenomatous polyposis (FAP) who undergo colectomy with ileorectal anastomosis (IRA) are at risk of adenoma recurrence and malignant transformation in the residual rectum. Advances in endoscopic techniques have enabled intensive surveillance with aggressive polypectomy to reduce the short-term risk of malignant progression. However, long-term management often requires a balance between endoscopic management and timely surgical intervention, and evidence to guide this balance remains limited.