Postmastectomy electron-beam chest-wall irradiation in women with breast cancer

This retrospective study evaluates the results of postmastectomy electron-beam chest-wall irradiation in patients with breast cancer. From 1980 to 1994, 144 women with localized breast cancer received postmastectomy radiotherapy. The chest wall was irradiated by electron beam, 6 to 12 MeV energy, depending on wall thickness, 2.0 Gy daily, 5 times/week for total dose of 50 Gy. Forty-one patients received 16-Gy boosts to the mastectomy scar. In addition, the supraclavicular and axilla areas were irradiated by anterior field with 6-MV photon beam. Median follow-up was 84 months. Fifteen patients (10%) had local-regional recurrence (LRR) and 57 patients (40%) had systemic relapse (SR). Median time from mastectomy to LRR was 20 months and median time to SR was 33 months. Axillary lymph nodes status influenced both LRR and SR. LRR rate was 0% in N0 and 12% in N1 disease; SR rate was 14% in N0 and 45% in N1 disease. Disease-free and overall survival was 58% and 67% in 10 years and 50% and 55% in 20 years, respectively. No cardiac toxicity was related to left chest-wall irradiation. Postmastectomy electron-beam chest-wall irradiation is as effective as photon-beam irradiation in breast cancer.