Long-term cosmesis following a novel schedule of accelerated partial breast radiation in selected early stage breast cancer: result of a prospective clinical trial

PURPOSE: There is controversy regarding the cosmetic outcome after accelerated partial breast radiation (APBR). We report the cosmetic outcome from a single-arm prospective clinical trial of APBR delivered using intensity-modulated radiation therapy (IMRT) in elderly patients with stage I breast cancer (BC), using a novel fractionation schedule. MATERIALS AND METHODS: Forty-two patients aged ≥65, with Stage I BC who underwent breast-conserving surgery were enrolled in a phase I/II study evaluating a 2-week course of APBR. Thirty eligible patients received 40 Gy in 4 Gy daily fractions. Cosmetic outcome was assessed subjectively by physician/patient and objectively by using a computer program (BCCT.core) before APBR, during, and after completion of the treatment. RESULTS: The median age was 72 years, the median tumor size was 0.8 cm, and the median follow-up was 50.5 months. The 5-year locoregional control in this cohort was 97% and overall survival 87%. At the last follow-up, patients and physicians rated cosmesis as ‘excellent’ or ‘good’ in 100% and 91 %, respectively. The BCCT.core program scored the cosmesis as ‘excellent’ or ‘good’ in 87% of the patients at baseline and 81% at the last follow-up. The median V(50) (20 Gy) of the whole breast volume (WBV) was 37.2%, with the median WBV V(100) (40 Gy) of 10.9%. CONCLUSION: An excellent rate of tumor control was observed in this prospective trial. By using multiple assessment techniques, we are showing acceptable cosmesis, supporting the use of IMRT planned APBR with daily schedule in elderly patients with early stage BC.