Associations Between Cardiac Radiation Dose-Volume Metrics and Health-Related Quality of Life for Patients With Breast Cancer on the RadComp Trial.

In 30 seconds

This analysis of the pragmatic randomised RadComp trial examined cardiac radiation doses and health-related quality of life (HRQOL) in 1160 patients with breast cancer who had dose-volume data and baseline plus follow-up assessments within 6 months after radiotherapy. Proton therapy delivered a lower mean whole-heart dose than photon therapy: 0.89 Gy (relative biological effectiveness) versus 2.99 Gy (P< .001); doses to several cardiac substructures were also lower with protons. Patient-reported measures were generally favourable, and no cardiac dose-volume metric was significantly associated with early cardiac-related HRQOL outcomes.

Key findings

• Mean whole-heart dose was 0.89 Gy (relative biological effectiveness) with protons versus 2.99 Gy with photons (P< .001).
• Mean doses to the left ventricle, left atrium, and left anterior descending artery were also lower with protons (P < .001).
• No cardiac dose-volume metric was significantly associated with cardiac-related HRQOL outcomes during the 6 months after radiotherapy.
• Grade ≥3 toxicity was uncommon (≤5.5%) across the reported patient-reported measures.

Why it matters

The findings distinguish dosimetric advantages from demonstrated patient-reported benefit: proton therapy reduced exposure to the heart and several substructures, but these dose differences were not associated with early HRQOL outcomes in this analysis. This helps frame cardiac dose reduction as an important treatment-planning measure while underscoring that its relationship to symptoms and quality of life may not be apparent over short follow-up.

What to keep in mind

The analysis assessed HRQOL only during the 6 months after radiotherapy, so it does not establish associations with later outcomes.