The effects of irradiation on breast cancer and the breast.

The pathologic changes in tissues from 100 women who had received radiation therapy for breast cancer were studied. It is concluded that carcinoma of the breast cannot be considered a radiosensitive tumor, that irradiation should not be considered conservative treatment, and that radiotherapy is not innocuous. More studies of post-irradiation breasts are needed, from biopsy, surgical, and autopsy specimens. These studies should evaluate the tissues for the presence or absence of tumor, for radiation changes in the breast and the tumor, for evidence of tumor regression, for multicentricity, and for histologic types and patterns. Until this is done, the final results of radiation therapy for carcinoma of the breast will remain unknown.