A single-institution prospective cohort provides real-world data on ultra-hypofractionated whole-breast radiotherapy delivered in five fractions, with favourable tolerability and early tumour-control results. The regimen was applied in a risk-adapted way, including an alternative schedule for when a boost was indicated but not feasible.
What was already known
Five-fraction ultra-hypofractionated adjuvant whole-breast irradiation is effective in early-stage breast cancer, as demonstrated by the FAST-Forward trial. The work described here implemented a risk-adapted programme and reports the real-world tolerability and early outcomes of this approach.
What this work adds
This is a prospective single-institution observational study that included 718 patients with stage 0 to IIIA breast cancer treated after breast-conserving surgery between 2020 and 2024. Patients received 26 Gy in five daily fractions (with or without a moderately hypofractionated sequential boost of 10-12.5 Gy in 4-5 fractions) or 28 Gy in five twice-weekly fractions instead of a boost (n = 201). Acute and late toxicity, patient-reported outcomes and cosmesis were prospectively assessed at follow-up visits.
Main results
No grade ≥3 acute toxicity occurred; 13% developed grade 2 acute skin reactions. At a median follow-up of 27 months, late toxicity was low: 11% of patients had any grade ≥2 late effect (3% grade 3). The 3-year cumulative incidence of ipsilateral in-breast recurrence was 0.6% and 3-year overall survival was 98.5%. Exploratory comparisons detected no significant toxicity differences among regimens. Larger breast volume was associated with acute and late toxicity. Cosmesis was good or excellent in 98% of patients.
What it means
The authors conclude that risk-adapted five-fraction radiotherapy was well tolerated with excellent early tumour control, and that the 28 Gy twice-weekly schedule shortened treatment when a boost was infeasible without compromising early-to-intermediate outcomes. These findings support routine adoption of ultra-hypofractionated adjuvant radiotherapy in early breast cancer, pending long-term follow-up to confirm safety.
A breast-unit perspective
Five-fraction schedules markedly reduce the number of treatment visits compared with conventional courses, which can ease the care burden and help organise radiotherapy schedules within a breast unit. Risk adaptation and consideration of breast volume are elements worth keeping in mind when planning each case.
Reference: Unterkirhere O, Streller T, Jeller D, Logaritsch P, Arnold M, Bucher S, et al. Ultra-Hypofractionated Whole-Breast Irradiation: Real-World Data From a Prospective Single-Institution Cohort. Clinical Breast Cancer, 2026. DOI/link
