Why the study?
Relationships between radiation therapy dose to cardiac substructures and patient-reported outcomes assessed by health-related quality of life remain unknown.
Does proton RT compared with photon RT reduce cardiac radiation dose and improve cardiac-related health-related quality of life in patients with breast cancer?
Does proton RT compared with photon RT reduce cardiac radiation dose and improve cardiac-related health-related quality of life in patients with breast cancer?
While proton therapy significantly reduces radiation exposure to the heart and its substructures compared to photon therapy in breast cancer patients, this dosimetric advantage does not translate into measurable differences in early cardiac-related quality of life at 6 months.
No cardiac substructure dose linked to early HRQOL in breast RT RCT; challenges prior assumptions and leaves open longer-term cardiac symptom relationships.
PURPOSE: Relationships between radiation therapy (RT) dose to cardiac substructures and patient-reported outcomes, as assessed by health-related quality of life (HRQOL), remain unknown. We sought to: (1) compare RT dose to cardiac substructures in patients treated with proton versus photon RT on the Radiotherapy Comparative Effectiveness (RadComp) pragmatic randomized clinical trial, which compared proton versus photon RT in breast cancer; (2) evaluate whether there were changes in HRQOL outcomes from baseline to 6 months following RT; and (3) determine the potential associations between radiation dose-volume histogram (DVH) parameters and changes in cardiac-related HRQOL. METHODS AND MATERIALS: , maximum dose, mean dose, and percent volume receiving a specified dose. HRQOL measures that we hypothesized could provide some insights into cardiac symptoms included Patient-Reported Outcomes Measurement Information System (PROMIS) fatigue, Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) shortness of breath and chest pain, chest tightness, and angina. RESULTS: The mean dose to the whole heart was lower with protons, 0.89 Gy(relative biological effectiveness (RBE)) (Q1-Q3, 0.49-1.39), compared with photons 2.99 Gy (Q1-Q3, 1.60-4.61) (P< .001), as was the mean dose to the left ventricle, left atrium, and left anterior descending artery (P < .001). PRO-CTCAE measures were favorable at all time points with only modest changes observed, and grade ≥3 toxicity was uncommon (≤5.5%) for all measures. No DVH metrics were significantly associated with any cardiac-related HRQOL outcomes over the 6 months post-RT when evaluated by treatment arm or laterality. CONCLUSIONS: Proton RT generally conferred significantly lower doses to the heart and cardiac substructures compared with photon RT. PRO-CTCAE measures were favorable overall. No cardiac DVH parameters were associated with early HRQOL outcomes.
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Jt et al. (2026) studied this question.
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