Gastrointestinal bleeding/ulcer among paediatric cancer patients after proton beam therapy.

Patients who developed gastrointestinal bleeding/ulcer were treated concurrently with vincristine-cyclophosphamide-ifosfamide-etoposide or vincristine-cyclophosphamide, and their ages were older than those of patients without gastrointestinal bleeding/ulcer. Bleeding occurred in the upper gastrointestinal tract in all the cases, and most cases occurred early and during chemotherapy. Upper gastrointestinal irradiation in older children undergoing intensive chemotherapy may increase the risk of developing gastrointestinal complications.