Radiotherapy as an adjuvant in the treatment of carcinoma of the breast.

During the period from 1950-1974, 510 patients with a diagnosis of invasive ductal carcinoma treated with the standard Halsted radical mastectomy were reviewed retrospectively from the records of the Tumor Clinic of The Memorial Hospital, Danville, Virginia. The primary aim of the study was to determine whether postoperative adjuvant radiation therapy (POART) as delivered in a community hospital setting contributed to better cancer control and effectively influenced five and ten year survival rates. The results of the review indicated that the use of POART whether from an orthovoltage or cobalt source did not differentially influence the patient's disease outcome. The use of POART did not improve the five- and ten-year survival rates regardless of lesion location in patients with Stages I, II, and III disease with positive lymph nodes. POART did cause a significant decline in five- and ten-year survival rates of patients with Stage II and III disease with negative nodes when compared to the survival of patients with the same stage of disease that did not receive POART, i.e., 75% versus 94% five-year difference, and a 65% versus 85% ten-year difference. These results suggest that radiotherapy may have a detrimental effect on immunocompetence and thus alter survival rates in certain circumstances. Therefore, any clinical investigation measuring the results of various therapeutic modalities singularly or in combination should be based on pathologic staging rather than clinical staging so that these factors can be adequately evaluated.