Background: Between 1979-1987, the National Cancer Institute conducted a randomized, prospective study of mastectomy (MT) versus breast conservation therapy (BCT) in the treatment of patients with early-stage breast carcinoma. After a median potential follow-up of 18.4 years, the authors present the updated results.
Methods: After informed consent was obtained from each patient, 237 evaluable women with clinical AJCC Stage I and Stage II breast carcinoma were enrolled on an institutionally reviewed protocol and randomly assigned to undergo modified radical MT (116 patients) or BCT (121 patients), which was comprised of lumpectomy, axillary lymph node dissection, and radiation therapy. Negative surgical margins in the lumpectomy arm were not required. The 237 randomized patients were followed for a median potential follow-up of 18.4 years. The primary endpoints were overall survival and disease-free survival.
Results: At a median follow-up of 18.4 years, there was no detectable difference with regard to overall survival between patients treated with MT and those treated with BCT (58% vs. 54%; P = 0.67 overall). Twenty-seven women in the BCT arm (22%) experienced an in-breast event. After censoring in-breast events in the BCT arm that were salvaged successfully by MT, disease-free survival also was found to be statistically similar (67% in the MT arm vs. 63% in the BCT arm; P = 0.64 overall). There was no statistically significant difference with regard to contralateral breast carcinoma between the two treatment arms (P = 0.70).
Conclusions: After nearly 20 years of follow-up, there was no detectable difference in overall survival or disease-free survival in patients with early-stage breast carcinoma who were treated with MT compared with those treated with BCT. For BCT patients, long-term in-breast failures continued to occur throughout the duration of follow-up. There was no statistically significant difference in the incidence of contralateral breast carcinoma between the two treatment groups.