Patient-Reported Outcomes and Cosmesis After Once-Weekly Hypofractionated Breast Irradiation in Medically Underserved Patients.

PURPOSE: To evaluate patient-reported outcomes (PROs) and cosmesis from a phase 2 trial of once-weekly hypofractionated breast irradiation (WH-WBI) after breast-conserving surgery (BCS). METHODS AND MATERIALS: Patients had stage 0-II breast cancer treated with BCS and negative margins. WH-WBI was 28.5 to 30 Gy in 5 weekly fractions of 5.7 to 6 Gy delivered with or without a boost. PROs were collected for 3 years after treatment using the Breast Cancer Treatment Outcome Scale (BCTOS) and European Organization for Research and Treatment of Cancer Breast Cancer-Specific Quality of Life Questionnaire (QLQ-BR23). Physicians rated cosmetic outcome with the Global Cosmesis Score. Longitudinal growth models were used to assess changes in BCTOS across time, and baseline values and changes between time points were correlated with patient and treatment factors. RESULTS: From 2011 to 2015, 158 women received WH-WBI, and 148 were eligible for analysis after a median follow-up of 39.3 months. Adverse changes (P < .001) in global BCTOS score and breast pain and arm function subscores were observed 6 months after radiation therapy, followed by improvement to near-baseline values at years 1 and 3. Adverse changes in BCTOS cosmetic subscore were also detected at 6 months (P < .001), with no significant improvement at 1 (P = .385) and 3 (P = .644) years. No effect was detected for longitudinal changes in BCTOS scoring for age, body mass index, diabetes, smoking, breast volume, tumor size, seroma volume, dosimetric factors, dose, boost, or systemic therapy. Physician-rated cosmesis at 3 years was excellent/good in 89% and fair/poor in 11%. CONCLUSIONS: WH-WBI was associated with transient worsening in arm function and breast pain but persistent adverse changes in cosmetic PROs that were typically mild or moderate in severity. Physician-rated cosmetic outcomes were acceptable.