Adjuvant Radiation Improves Survival in Older Women Following Breast-Conserving Surgery for Estrogen Receptor-Negative Breast Cancer.

PURPOSE: Published prospective trials have questioned the role of post-lumpectomy radiotherapy in older women with early-stage, estrogen receptor-positive (ER+ ) breast cancer. As the population with ER- tumors may be at greater risk for relapse, particularly given that endocrine therapy is not effective, we hypothesize the addition of radiation would be of benefit in patients age ≥ 70.

METHODS AND MATERIALS: The Surveillance, Epidemiology, and End Results database was queried from 1998 to 2011 for patients age ≥ 70 years receiving breast-conserving surgery for T1, ER- invasive ductal carcinoma. Patients were separated into 2 cohorts: those treated with and without adjuvant radiotherapy. Chi-square analysis, unpaired t test and Kaplan-Meier log-rank were used to compare patient and tumor characteristics as well as overall and cancer-specific survival between the cohorts.

RESULTS: Overall, 3685 patients received radiation and 1493 patients received lumpectomy alone. Patients treated with adjuvant radiation were younger (median age 76 vs. 78 years, P < .0001). Patients who received radiation had improved overall survival, with 5-year survival rates of 81.0% versus 61.7% without radiation (P < .0001). Cancer-specific survival was also improved with radiotherapy, with 5-year cancer-specific survival rates of 93.1% versus 85.0% (P < .0001).

CONCLUSIONS: This analysis of the SEER database demonstrates that women ages 70 and older treated with lumpectomy and radiotherapy for ER- , early-stage breast cancer have improved overall survival and breast cancer-specific survival compared with patients treated with lumpectomy alone. This information may help in the decision-making process for this patient population.