The possible carcinogenic effects of radiations on the uterus.

The carcinogenic effects of radium and X-rays on the rat uterus have been investigated. Malignant endometrial tumours, usually adenocarcinomas, were produced in a small proportion of treated rats. One rat treated with X-rays developed an adeno-sarcoma (possibly carcino-sarcoma) of the endometrium. Benign mixed polypoidal endometrial tumours occurred also in radium and X-ray treated rats and in non-radiated controls; radiation increased the incidence of these tumours and may have induced malignant transformation in some. The incidence of lymphosarcomas and mammary tumours in the strain of rat used appeared to be influenced by radiation treatment.Review of the literature of human cases of mixed uterine tumours showed that in women over 40 years, more than one-fifth of the reported cases had a history of previous pelvic radiation; with other kinds of uterine malignancy a history of prior radiation treatment was considerably less. The results of our experiments enhance the suspicion that radiations are one factor in the causation of uterine cancer, especially mixed tumours.