Once-Weekly Hypofractionated Radiation Therapy in Breast Cancer: A Phase 2 Trial

Abstract

Hypofractionated radiotherapy in 15 or 16 daily fractions is well established as an alternative in early breast cancer after breast-conserving surgery. The evidences for a whole-breast treatment even shorter in 5-10 fractions are still scarce. The objective of the presenting study is to analyse the effects of adjuvant breast cancer radiation using a once-weekly schedule, in 5 fractions. Women 50 years or older, with early breast tumor with negative lymph nodes (pT1-2N0), after breast-conserving surgery with negative margins were eligible to enter in this phase II trial and received whole breast once-weekly hypofractionated radiotherapy to a total dose of 30 Gy, in 5 weekly fractions of 6 Gy. During the treatment and in post treatment follow-up the toxicity was assessed and graduated according the “Common Terminology Criteria for Adverse Events ” (CTCAE), v3.0. The quality of life was evaluated by the EORTC QLQ-30 e QLQ-BR23 questionnaires, that were applied before radiation, immediately after and 1 month after treatment. Breast pictures for aesthetic evaluation were taken in 5 moments and two breast surgeons independently graduated the cosmetics changes. From October 2013 to November 2015, 44 patients were enrolled in the trial and treated according to the protocol of once-weekly radiation. The median age was 70.5 years (51-88 years), and the median follow-up was 22 months (9-33 months). Actinic dermatitis was the most common acute adverse event. At the end of radiation, 30 patients (68,2%) had any grade of radiation dermatitis. Breast pain and hyperpigmentation were the most frequent late events. By the end of the first year of follow-up 53,8% and 51,3% developed breast pain and hyperpigmentation, respectively. Concerning the aesthetic evaluation, for only one of the two observers there was breast appearance alteration over time. For this observer, 63,6% and 13,6% of cases were classified as good or excellent in the evaluations before and after radiotherapy, respectively. After 6 months of treatment completion, 59,1% and 61,4% were aesthetic evaluated as good or excellent by each of the observers. The domain for “social function” was the only one that changed overtime in the quality of life analysis. One month after radiotherapy the median score for “social function” was greater compared to before treatment. The 2-year overall survival and disease-free survival were, respectively 96,8% and 97,7%. There was only one distant recurrence and no local or regional recurrences. Once-weekly hypofractionated radiotherapy is a feasible alternative in early breast cancer management with acceptable acute toxicity and aesthetic alterations and no meaningful quality of life impairment.