Long-term Impact of CALGB 9343 on Radiation Utilization.

Background: The results of the Cancer and Leukemia Group B (CALGB) 9343 trial showed that radiation therapy (RT) did not improve survival for women older than 70 y with early-stage estrogen receptor + breast cancer treated with breast conserving surgery and adjuvant endocrine therapy. In 2005, guidelines were modified to allow for RT omission; however, minimal change in clinical practice has occurred. The aim of this study was to determine if CALGB long-term follow-up data have affected RT utilization, and to characterize the population still receiving RT after breast conserving surgery.