Concurrent or sequential adjuvant hormonoradiotherapy after conservative surgery for early stage breast cancer: First results of the CO-HO-RT phase II randomized trial

Abstract

556 Background: We recently showed in an aromatase-gene transfected breast cancer cell line, a radiosensitizing effect of letrozole. We then conducted a multicentric phase II randomized trial evaluating adjuvant concomitant radiotherapy and letrozole with radiotherapy followed by letrozole in postmenopausal early breast cancer patients (CO-HO-RT trial). Methods: Postmenopausal pts with early stage breast cancer were randomized after conservative surgery to either: A) concurrent RT-LET (LET started 3 weeks before the first day of RT) or B) sequential RT-LET (LET started 3 weeks after the end of RT). Whole breast RT was delivered to a total dose of 50 Gy ± a 10–16 Gy boost. Pts were stratified by center, adjuvant chemotherapy (ACT), boost, CD8 radiation-induced apoptosis. Primary endpoint was radiation-induced acute and late skin toxicity. Skin toxicities were evaluated by two different clinicians at each medical visit (CTCAE v3.0). Lung CT-scan and functional pulmonary tests were performed regularly. Quali...