Abstract
Therapy-associated polyposis (TAP), an acquired gastrointestinal polyposis in childhood cancer survivors, poses diagnostic challenges resembling hereditary syndromes. Four TAP patients were studied, revealing upper gastrointestinal lesions after radiotherapy in 2 patients, managed by endoscopic resection. Two underwent total colectomy; 1 had adenocarcinoma from a polyp. Next-generation sequencing on diseased tissue revealed no alteration in mismatch repair genes with stable microsatellite status; however, there was somatic mutation in APC gene altering Wnt signaling pathway in all 3 precancerous lesions. Integrating endoscopic and surgical interventions is crucial, although ongoing studies aim to elucidate pathophysiology for potential targeted therapies in TAP management.