Prospective monitoring of the clinical implementation of ultrahypofractionated whole-breast radiotherapy using electronic patient-reported outcome measures.

BACKGROUND AND PURPOSE: Clinical trials on ultrahypofractionated (UHF) whole‑breast radiotherapy demonstrated non‑inferiority to moderate hypofractionation (HF). However, real-world evidence using modern treatment techniques, captured by fully automated electronic patient-reported outcome measures (ePROM), remains limited. This study prospectively evaluated the clinical implementation of UHF whole-breast radiotherapy using intensity-modulated/volumetric arc radiotherapy (IMRT/VMAT) with ePROM-based adverse event monitoring.

MATERIALS AND

METHODS

In this single-centre prospective cohort, consecutive non-metastatic breast cancer patients (breast conserving surgery, no nodal and no boost irradiation) received either HF (15 × 2.67  Gy) or UHF (5 × 5.2  Gy). Acute and late side effects were assessed using PRO‑CTCAE items (itching, radiation skin reaction, skin darkening, pain and breast tenderness) via an automated ePROM platform at the first and last fraction, and at 3, 6, 9, 12, and 24  months. Longitudinal adverse event grades were modelled using population-averaged ordinal generalised estimating equations adjusted for age, surgery, and hormone therapy.

RESULTS

The patient cohort of 308 patients included 177 UHF and 131 HF patients. ePROM completion adherence was high (30% drop-out at 24 months). No clinically meaningful differences in adverse event severity were observed between both regimens, except for higher radiation skin reactions at the last fraction in HF (odd ratio (OR) = 2.70). At 24 months, only pain severity differed, with higher odds for HF (OR = 3.08). Other endpoints showed no significant between-group differences.

CONCLUSION

UHF whole-breast radiotherapy delivered with contemporary IMRT/VMAT showed no increase in acute or late patient-reported adverse events compared with HF, confirming its safe integration into clinical routine.