Local control, toxicity, and cosmesis in women >70 years enrolled in the American Society of Breast Surgeons accelerated partial breast irradiation registry trial

Purpose The American Society of Breast Surgeons enrolled women in a registry trial to prospectively study patients treated with the MammoSite Radiation Therapy System breast brachytherapy device. The present report examined the outcomes in women aged >70 years enrolled in the trial. Methods and Materials A total of 1,449 primary early stage breast cancers were treated in 1,440 women. Of these, 537 occurred in women >70 years old. Fisher’s exact test was performed to correlate age (≤70 vs. >70 years) with toxicity and with cosmesis. The association of age with local recurrence (LR) failure times was investigated by fitting a parametric model. Results Older women were less likely to develop telangiectasias than younger women (7.9% vs. 12.4%, p = 0.0083). The incidence of other toxicities was similar. Cosmesis was good or excellent in 92% of the women >70 years old. No significant difference was found in LR as a function of age. The 5-year actuarial LR rate with invasive disease for the older vs. younger population was 2.79% and 2.92%, respectively ( p = 0.5780). In women >70 years with hormone-sensitive tumors ≤2 cm who received hormonal therapy ( n = 195), the 5-year actuarial rate of LR, overall survival, disease-free survival, and cause-specific survival was 2.06%, 89.3%, 87%, and 97.5%, respectively. These outcomes were similar in women who did not receive hormonal therapy. Women with small, estrogen receptor-negative disease had worse LR, overall survival, and disease-free survival compared with receptor-positive patients. Conclusions Accelerated partial breast irradiation with the MammoSite radiation therapy system resulted in low toxicity and produced similar cosmesis and local control at 5 years in women >70 years compared with younger women. This treatment should be considered as an alternative to omitting adjuvant radiotherapy for older women with small-volume, early-stage breast cancer.