Carcinomas of the female genital tract occurring after pelvic irradiation: a report of 15 cases.

The concept of postradiation sarcoma is widely appreciated, however carcinomas arising in previously irradiated fields, the putative "postradiation carcinoma," are less well understood. Fifteen patients who developed gynecological malignancies after pelvic radiation therapy were studied. Five of these patients had HPV-related tumors both pre- and post- irradiation. Ten were irradiated for cervical cancer, one for endometrial carcinoma, one for vulvar carcinoma, one for colon cancer and 2 for benign conditions. The mean and median latent periods from the initiation of radiation therapy to the development of the second malignancy were 22.8 and 19 years, respectively (22.4 and 19.5 years, respectively, for non-HPV-related cancers; 24 and 18 years for HPV-related cancers). The "postradiation" malignancies included 2 ovarian carcinomas, 5 vaginal carcinomas (3 invasive, 2 in situ), 4 endometrial carcinomas, one cervical carcinoma, one vulvar carcinoma, one distal urethral carcinoma, and one pelvic carcinoma of unclear primary site. Gynecological carcinomas may occur many years after pelvic irradiation. Although the evidence for a causative role is circumstantial, these tumors appear to have a similar latent period as postradiation sarcomas.