Hypofractionated Versus Conventional Fractionated Radiotherapy for Patients with Triple Negative Breast Cancer: A Single Institution Randomized Trial

Introduction: Delivering hypofractionated radiotherapy schedules for patients with breast cancer is a growing interest. The current study aimed to determine whether hypofractionated radiotherapy is as effective and safe as conventional fractionated radiotherapy for patients with triple negative breast cancer, irrespective of lymph node status or surgical type. Methods: The current study is a randomized, open-label trial. A total of 148 female participants with non-metastatic triple negative breast cancer (TNBC) were recruited from January 2019 to December 2023. Eligible participants were randomly assigned (1:1) for hypofractionated schedule or conventional radiotherapy schedule. The trial included all nonmetastatic TNBC eligible to adjuvant radiotherapy due to positively involved lymph nodes or high-risk features of the primary tumor. The 3- year Loco-regional recurrence free survival (RFS) was the primary end point. Results: At a median follow-up of 24 months, seven (5.3%) patients had developed locoregional recurrence, all of them in hypofractionated radiotherapy (RT) arm. The 3-year Loco-regional RFS rate was significantly higher in conventional RT arm compared to the hypofractionated RT arm (p <0.001). The 3-year distant metastases free survival was not significantly differed in the two groups (p =0.121). The 3-year overall survival was 90.4%, with no significant difference between the groups (p= 0.091). Conclusion: The effectiveness of hypofractionated radiotherapy for disease control of triple-negative disease, irrespective of lymph node status or type of surgical interference remains questionable.