Combined Ultrahypofractionated Whole-Breast Irradiation and IORT-Boost: A Safety and Feasibility Analysis

Abstract

The aim of the present study is to assess, for the first time, the feasibility and safety of combining photon IORT with ultrahypofractionated WBI after breast-conserving surgery (BCS). From July 2020 to December 2022, seventy-two patients diagnosed with low-risk early BC were included in this prospective study. IORT was administered at a dose of 20 Gy to the surface's applicator, and WBI was to be administered 3-5 weeks after surgery at a total dose of 26 Gy in five consecutive days. All patients completed the proposed treatment schedule, and no severe acute or late grade 3 toxicity was observed at 3 and 12 months after WBI, respectively. Our results confirm, for the first time, that the combination of ultrafractionation WBI after BCS and photon-IORT is a feasible and safe option in patients with early BC.Abstract Background: The current standard of local treatment for patients with localized breast cancer (BC) includes whole breast irradiation (WBI) after breast-conserving surgery (BCS). Ultrahypofractionated WBI schemes (1-week treatment) were shown not to be inferior to the standard WBI. Tumor bed boost using photon intraoperative radiotherapy (IORT) is safe and feasible in combination with standard WBI. The aim of the present study is to assess, for the first time, the feasibility and safety of combining photon IORT with ultrahypofractionated WBI. Methods: Patients diagnosed with low-risk early BC candidates for BCS were included in this prospective study. IORT was administered at a dose of 20 Gy to the surface's applicator, and WBI was administered 3-5 weeks after surgery at a total dose of 26 Gy in five consecutive days. Results: From July 2020 to December 2022, seventy-two patients diagnosed with low-risk early BC and treated in our institution were included in this prospective study. All patients completed the proposed treatment, and no severe acute or late grade 3 toxicity was observed 3 and 12 months after WBI, respectively. Conclusions: Our results confirm for the first time that the combination of ultrafractionation WBI and photon-IORT after BCS is a feasible and safe option in patients with early BC.