Abstract
Patients who have received pelvic irradiation are reported to be at increased risk of subsequently developing malignancies of the large bowel. We report five cases of rectal carcinoma, one early cancer and four advanced cancers, that developed following pelvic irradiation for the uterine cervical and corpus cancer. The mean age of the patients was 70 years (range, 64 to 77 years), and the mean interval between irradiation and surgery for rectal cancer was 12.9 years (range, 5 to 25 years). Radiation-induced changes in the remaining bowel were recognized in all five patients, and four of them had symptoms of radiation proctitis. One of the five tumors was histologically diagnosed as well differentiated adenocarcinoma and the other four as moderately differentiated adenocarcinoma. Histopathological examination revealed that all four advanced carcinomas included a deep ulcer covered with necrotic tissue that contained many blood cells on its surface. Three of the four patients with advanced rectal cancer died within 2 years after surgery, indicating a poor prognosis for radiation-induced rectal carcinoma. Long-term follow-up with careful surveillance for colorectal cancer is required in patients who have undergone pelvic irradiation.
