Carcinoma of large intestine in patients irradiated for carcinoma of cervix and uterus

Twenty-six patients with carcinoma of colon and rectum following radiation therapy for cancer cervix and uterus have been analyzed. Nearly two thirds of the patients were more than 60 years old. The interval between irradiation and diagnosis of the second tumor varied from 5 to 30 years. Despite lack of detailed information on radiation factors in half of the patients, circumstantial evidence from this study suggests that radiation therapy may have contributed to the development of colorectal adenocarcinoma in some of the patients. Among the findings supporting this conclusion in this series are: 1. localization of second tumor at site of radiotherapy; 2. 58% of the patients had symptomatic and clinically documented chronic radiation proctocolitis at sites of subsequent tumor; 3. 69% of the patients had post-irradiation interval of more than 10 years; 4. 58% of the patients had histologic proof of radiation-related alterations in involved bowel segment; 5. occurrence of a much higher than expected percentage (58%) of mucinous (colloid) adenocarcinoma in involved region, of which 92% had clinical and/or histologic evidence of radiation proctocolitis. The overall and determinate 5-year survival in this series was 20% and 22%, respectively. It, therefore, behooves the clinician to be vigilant in the follow-up of these patients who are long-term survivors of radiation-treated carcinoma of cervix and uterus for the late development of colorectal carcinoma.