Financial Toxicity of Shorter Versus Longer Partial Breast Irradiation: A Randomized Clinical Trial.

Document Type

Article

Publication Title

International journal of radiation oncology, biology, physics

Abstract

PURPOSE: Within a randomized clinical trial comparing partial breast irradiation (PBI) dosing schedules, we sought to determine whether shortening the radiation course would reduce financial toxicity (FT).

METHODS AND MATERIALS: In a phase 3 trial of 778 women aged ≥40 years who underwent segmental mastectomy for early breast cancer at 12 US cancer centers, patients were randomized 1:1 to external beam PBI using 15-22 fractions (control, n = 385) versus 513 fractions (experimental, n = 393) (NCT03077841). FT was assessed using comprehensive, multi-item instruments and scored using the Economic Strain and Resilience in Cancer measure at baseline, end of radiation treatment (EoT), and 6- and 18-months after radiation on a scale of 0-100 (higher score indicated worse FT). Mixed linear multivariable regression estimated adjusted difference-in-differences between EoT versus baseline FT by treatment arm. Minimal important difference (MID) in Economic Strain and Resilience in Cancer score from baseline to EoT was estimated, anchored on change in patient-reported overall financial situation during that interval.

RESULTS: Treatment arms had balanced clinical and sociodemographic characteristics. Median PBI duration was 22 days (IQR, 21-25) for the control arm versus 7 days (IQR, 5-10) for the experimental arm (P < .001). FT measures were completed for 96.1% of baseline and EoT assessments (n = 1496/1556). Adjusted improvement in FT score between baseline to EoT was -2.0 (95% CI, -3.6 to -0.4; P = .02) for the experimental versus control arm. Of 52 individual FT items assessed, 9 favored the experimental arm at EoT (P < .05), whereas none favored the control arm. MID in Economic Strain and Resilience in Cancer score was 2.2 (95% CI, 1.0-3.4).

CONCLUSIONS: For patients with early breast cancer eligible for PBI, shortening the radiation duration by an average of 15 days yielded a reduction in end of treatment FT that was less than the MID estimated in this study.

DOI

10.1016/j.ijrobp.2026.05.046

Publication Date

6-15-2026

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