Report of Two Cases Developing Rectal Cancer after Pelvic Irradiation

Abstract

We report two cases who developed rectal cancer after pelvic irradiation. Both patients had histological changes associated with irradiation within the site adjacent to neoplastic area. We analyzed clinical courses and pathological findings of the 18 cases including previously reported 16 cases in Japan and our 2 cases. The average interval between irradiation and development of rectal cancer was 18.5 years. More than half of the patients (66.7%) had clinical and or histological radiation colitis. Occurrence of mucinous adenocarcinoma was 10.1%. The 5-year-survival was 25%.