Serial Measurement of Global Longitudinal Strain Among Women With Breast Cancer Treated With Proton Radiation Therapy: A Prospective Trial for 70 Patients.

Purpose: Conventional photon radiation therapy (RT) for breast cancer is associated with a reduction in global longitudinal strain (GLS) and an increase in troponin, N-terminal pro hormone B-type natriuretic peptide (NT-proBNP), and incident heart failure. The cardiac radiation exposure with proton-RT is much reduced and thus may be associated with less cardiotoxicity. The objective was to test the effect of proton-RT on GLS, troponin, and NT-proBNP.