Therapy-associated polyposis as a late sequela of cancer treatment

Abstract

Survivors of childhood cancers are at increased risk of developing secondary gastrointestinal cancers, including colorectal cancer, later in life, possibly from exposure to abdominopelvic radiotherapy and/or alkylating chemotherapy. Profuse gastrointestinal polyposis is associated with rare, inherited colorectal cancer predisposition syndromes, most commonly caused by mutations in the adenomatous polyposis coli (APC) or mutY homolog (MUTYH) genes. We describe 5 patients who developed gastrointestinal polyposis many years after radiotherapy and chemotherapy for a childhood cancer. Genetic analysis of all 5 subjects did not identify pathogenic germline mutations in APC or MUTYH. Chemotherapy and/or radiotherapy therefore might cause gastrointestinal polyposis in some patients by undiscovered mechanisms.

Keywords: Adenomas; Chemotherapy; Polyps; Radiation.

Figure

A, gastric inflammatory/hamartomatous polyp from Patient 1 (original magnification, 40×). B, ascending colon sessile serrated adenoma/polyp from Patient 2 (original magnification, 200×). C, descending colon tubular adenoma from Patient 3 (original magnification, 200×). D, descending colon mixed hyperplastic polyp/mucosal perineurioma from Patient 4 (original magnification, 200×). E, esophagogastroduodenoscopy from Patient 1 showing multiple gastric body inflammatory/hamartomatous polyps. F, colonoscopy from Patient 3 showing multiple rectal adenomas.