Moderately hypofractionated post-operative radiation therapy for breast cancer: Systematic review and meta-analysis of randomized clinical trials

Introduction: We provide a critical assessment regarding current evidence for the use of moderately hypofractionated irradiation for patients with breast cancer. The aim of the study was to summarize the available evidence regarding outcomes after moderately hypofractionated compared with conventional radiation doses in the post-operative treatment of patients with breast cancer. Material and methods: The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and LILACS databases were searched until March 25, 2021. All randomized phase 3 clinical trials that compared moderately hypofractionated with conventional radiation doses in the post-operative treatment of patients with breast cancer were selected. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. Results: Eight clinical trials satisfied the eligibility criteria and were the focus of the analysis. A total of 12,139 breast cancer patients was randomly assigned for moderately hypofractionated compared with conventional irradiation. Meta-analysis of the trials regarding local recurrence, loco-regional recurrence, disease-free survival, and overall survival outcomes did not demonstrate any significant difference between moderately hypofractionated irradiation and conventional radiation doses groups. The rate of severe side effects was low in both groups; acute and late side effects and cosmesis were similar or even tended to be lower after moderately hypofractionated than after conventional irradiation. Conclusions: Moderately hypofractionated is at least as effective and safe as conventional radiation irradiation regimens and should be considered as a treatment option for most, if not all, breast cancer patients.