Therapy-Associated Polyposis in Pediatric Cancer Survivors.

Childhood cancer survivors face lifelong risks requiring ongoing monitoring. We report three cases of survivors who subsequently developed colon polyps in their teens or twenties within 10 years of completing cancer treatment. They presented with gastrointestinal symptoms, leading to early colonoscopies revealing tubular adenomas and other polyps. None had a family history of colon cancer or positive germline testing. Two had a history of astrocytoma, and one a history of relapsed T-cell acute lymphoblastic leukemia; all had high cyclophosphamide equivalent doses (CED) of chemotherapy, and some received radiation. These observations suggest a diagnosis of therapy-associated polyposis (TAP) linked to alkylating agents in addition to radiation and the need for heightened clinical awareness of TAP in cancer survivors.