Effect of Addition of Adjuvant Paclitaxel on Radiotherapy Delivery and Locoregional Control of Node-Positive Breast Cancer: Cancer and Leukemia Group B 9344

Purpose We compared radiotherapy (RT) delivery and locoregional control in patients with node-positive breast cancer randomly assigned on Cancer and Leukemia Group B 9344 to receive adjuvant doxorubicin/cyclophosphamide (AC) with patients assigned to receive AC followed by paclitaxel (AC+T). Methods Eligible patients were randomly assigned to receive adjuvant AC versus AC+T chemotherapy. RT was required if breast-conserving surgery was performed but was elective after mastectomy. Information about RT delivery was retrospectively collected. Cumulative incidence of locoregional recurrence (LRR), use of elective RT, and RT delivery were compared between treatment arms. Results For patients treated with breast-conserving surgery and RT, the 5-year cumulative incidence of isolated LRR was 9.7% in the AC arm and 3.7% in the AC+T arm (P = .04) and of LRR as any component of failure was 12.9% versus 6.1%, respectively (P = .04). Although LRR rates in patients who did not receive postmastectomy RT were lower in th...