Acute Skin Toxicities After Ultrahypofractionated Versus Hypofractionated Postoperative Radiotherapy in Patients With...

Real-world safety data from Southeastern Europe are limited for ultrahypofractionated (UHF) whole-breast irradiation (WBI). We aimed to evaluate acute skin toxicity with UHF versus hypofractionated (HF) postoperative radiation therapy in early breast cancer, following implementation of this fractionation regimen.

This combined prospective-retrospective study included women aged ≥50 years following breast-conserving surgery (pT1-2, pN0-1, M0). The UHF cohort (prospective) received 26 Gy in 5 fractions over one week between 2023 and 2024. The control group consisted of retrospective data obtained from institutional records of patients who received WBI using a HF schedule of 40.5-42.6 Gy in 15-16 fractions over 3 weeks between 2015 and 2020. All patients were treated with 3D-CRT WBI without regional nodal irradiation or boost. Acute skin toxicity was graded by CTCAE v5.0 at end of treatment and at 4 and 12 weeks.

This study included 80 patients, with 40 in each group, with a mean age of 61.1 ± 6.6 years. Baseline clinicopathological characteristics were comparable, except for a slightly larger median tumor size in the UHF group (p = 0.037). At the end of radiation therapy, acute radiodermatitis occurred in 36 of 40 (90%) patients receiving UHF and in 38 of 40 (95%) patients receiving HF (p = 0.396). The grade distribution was comparable across the two groups (p = 0.53), and no grade ≥3 events were recorded. At 4 weeks, no adverse skin reactions were observed in patients receiving UHF, and by twelve weeks, no active radiodermatitis persisted in either group.

UHF WBI (26 Gy/5 fractions) demonstrated comparable acute skin toxicity to standard HF regimens, supporting its safety and clinical feasibility in routine practice.