Intraoperative Radiotherapy in Early-Stage Breast Cancer: Results of the Montpellier Phase II Trial

Abstract

We recently presented the intraoperative radiotherapy (IORT) technique given as a reliable alternative to conventional boost radiation after breast-conserving surgery. The low crude numbers of recurrence in elderly patients led us to investigate the feasibility and the efficacy of this procedure as a sole treatment. We included 94 patients older than 65 years in this phase II trial. Among them, 42 patients presented with all the inclusion criteria, i.e., stages pT0 to pT1 and pN0, ductal invasive unifocal carcinoma, and tumor-free margin of >2 mm. IORT was delivered using a dedicated linear accelerator. One 21-Gy fraction was prescribed and specified at the 90% isodose, using electrons. In vivo dosimetry was performed for all patients. The primary endpoint was the quality index. Secondary endpoints were quality of life, local recurrences, cosmetic results, and specific and overall rates of survival. The median follow-up was 30 months (range, 12-49 months), and median age was 72 years (range, 66-80 years). The median tumor diameter was 10 mm. All patients received the total prescribed dose. No acute grade 3 toxicities were observed. Endpoints for all but one patient corresponded to acceptable quality index criteria. Pretreatment quality-of-life scores were maximal, and no significant decrease was observed during follow-up. Cosmesis was good to excellent at 6 months. Two patients experienced recurrence but underwent salvage mastectomy. Our results confirm that exclusive partial-breast IORT is feasible for treating early-stage breast cancer in the elderly. IORT may be considered an alternative treatment for a selected population and offers a safe one-step treatment.