Accelerated Hypofractionated Whole Breast Radiotherapy for Early Breast Cancer; A Randomized Phase III Clinical Trial

To compare the cosmetic outcome and acute cutaneous, cardiac, and pulmonary toxicity profile of accelerated hypofractionated and conventional whole breast radiotherapy (WBRT).This was a blocked randomized, clinical trial on women with early-stage node-negative invasive breast cancer after breast conservation surgery (BCS) with clear margins randomly assigned to receive WBRT either at a conventional dose of 50.0 grays (Gy) in 25 fractions (the conventional group) or at a dose of 42.5 Gy in 16 fractions (the hypofractionated group). Boost irradiation was permitted in both groups. Data were analyzed by SPSS V21.0 using Mann–Whitney U, independent-samples t- and Chi-Square/Fisher's exact tests at the level of P≤0.05.The median follows up was 16 months. Forty-one patients in the conventional WBRT arm and 45 patients in the hypofractionated WBRT group were enrolled. No significant difference was observed in terms of left and right ventricle systolic dysfunction and diastolic dysfunction. Pulmonary function tests after 6 and 12 months follow up, were comparable in both groups (P=0.2). Skin toxicity during and after treatment was acceptable in both groups. Breast size change in the conventional and the hypofractionated WBRT groups was 14.3% and 7.1%, respectively (P=0.6). Excellent or good cosmetic outcome was similar in both groups.The results of our study support the use of accelerated hypofractionated WBRT in women with invasive breast cancer less than five cm and node-negative after breast-conserving surgery, which provides a more convenient shorter course of radiotherapy with a comparable cosmetic outcome and cutaneous, cardiac, and pulmonary toxicity profile.