Chest wall plus nodal radiation therapy for left-sided breast cancer significantly reduced global longitudinal strain from -17.50% to -15.32% (P=0.020), whereas whole-breast RT showed no such changes.
Cohort (n=64)
Does higher dose radiation therapy (chest wall plus nodal RT) increase acute cardiac injury measured by CMR strain compared to whole-breast RT in patients with left-sided breast cancer?
High-dose radiation exposure from chest wall plus nodal RT increases susceptibility to acute cardiac injury, which can be sensitively detected early by CMR-derived myocardial strain.
Absolute Event Rate: -15.32% vs -17.5%
p-value: p=0.020
PURPOSE Radiation therapy (RT) for breast cancer (BC) increases long-term cardiovascular risk; however, the early identification of acute cardiac injury remains critically underexplored. This study aimed to prospectively assess radiation-induced acute cardiac injury after postoperative left-sided BC RT using cardiac magnetic resonance (CMR) strain analysis. METHODS AND MATERIALS Patients with left-sided BC undergoing RT were prospectively enrolled. Radiation doses to cardiac structures were calculated. CMR scans were performed within 2 weeks before and after RT. RESULTS Among 64 enrolled patients, 41 received whole-breast RT (40.5 Gy/15 fractions; whole-breast RT WBRT group) and 23 received chest wall plus nodal RT (50 Gy/25 fractions; chest wall RT CWRT group). The mean cardiac dose in the CWRT group was higher than that in the WBRT group (mean heart dose MHD: 8.93 ± 2.67 Gy vs 2.80 2.25 to 3.61 Gy, P < .001; left ventricle LV: 9.50 ± 3.49 Gy vs 2.85 2.06 to 3.86 Gy, P < .001). The CWRT group demonstrated an increasing gradient of radiation dose from the basal to apical LV layers and a significant reduction in global longitudinal strain (GLS) (-17.50 -15.73 to -17.85% vs -15.32% ± 2.58%; P = .020) and global circumferential strain (GCS) (-20.34% ± 1.89% vs -19.22% ± 2.14%; P < .001) after RT, with similar alterations in the apical and middle layers, whereas the WBRT group showed no such changes. Among all patients, cardiac dosimetric parameters were independently associated with decreases in GLS and GCS (P < .05). Moreover, 10 patients (15.6%) developed cancer therapy-related cardiac dysfunction after RT; the combination of cardiac dose and the Systematic Coronary Risk Evaluation 2 risk index accurately predicted cancer therapy-related cardiac dysfunction (area under the curve, AUCMHD = 0.931; AUCLV-V5 = 0.925). CONCLUSIONS High-dose radiation exposure increases susceptibility to acute cardiac injury after left-sided BC RT. CMR-derived myocardial strain is a sensitive indicator of radiation-related acute cardiac dysfunction.
Zheng et al. (Sun,) conducted a cohort in Left-sided breast cancer (n=64). Chest wall plus nodal radiation therapy (CWRT) vs. Whole-breast radiation therapy (WBRT) was evaluated on Global longitudinal strain (GLS) before and after RT in the CWRT group (p=0.020). Chest wall plus nodal radiation therapy for left-sided breast cancer significantly reduced global longitudinal strain from -17.50% to -15.32% (P=0.020), whereas whole-breast RT showed no such changes.