P1355 Short-term cardiac side-effects from radiotherapy in women with breast cancer

Abstract

Abstract Introduction Breast cancer radiotherapy provides an apparent benefit for long-term survival and local recurrence rate. However, there is still much concern about the early and late radiation-induced cardiac toxicity. Therefore, various radiotherapy techniques have been developed to reduce the cardiopulmonary radiation doses in patients with left-sided breast cancer, who are at particular risk of developing post-radiation cardiac injury. Aim We sought to investigate the early effect of radiotherapy on left (LV) and right ventricular (RV) function in females subjected to this treatment. Methods Fifty left-sided breast cancer patients , who underwent adjuvant radiotherapy between May 2017 and May 2018 were included in the study. Forty-nine enrollees were initially treated with breast conserving surgery, and 1 - with mastectomy and axillary lymph node resection. Adjuvant radiotherapy was carefully planned to minimize the radiation side effects and 37 patient received radiotherapy with deep inspiration breath hold technique and 13 patients with free breathing technique. In most cases (n = 33), 3D conformal tangential field radiation therapy was applied, 13 patients received radiotherapy with dynamic-Rapid-Arc technique with additional 3D fields, and 4 patients underwent radiotherapy only with Rapid-Arc technique. Before surgery and 3 months after radiotherapy, echocardiography with measurement of conventional cardiac function parameters, as well as LV and RV longitudinal deformation analysis by speckle tracking technique was performed, and venous blood for biomarkers - galectin-3 reflecting myocardial fibrosis and NT-proBNP was sampled. Results At a mean follow-up of 97 ± 19 days , there were no significant changes in any of the studied cardiac systolic or diastolic function parameters (Table). There were no relationships between the change in LV longitudinal strain at follow-up and type of radiotherapy, as well as type of radiotherapy gating (both R = 0.02, p = 0.90). Similarly, no analogous associations were demonstrated for RV longitudinal strain (R = 0.02, p = 0.88, and R = 0.04, p = 0.77, respectively). No significant changes were found post radiotherapy in serum galectin-3 (7.2 ± 2.6 ng/ml vs. 6.8 ± 2.5 ng/ml; p = 0.58) and NT-proBNP (83 ± 68 pg/ml vs. 84 ± 54 pg/ml; p = 0.90). Conclusions Breast cancer radiotherapy with the use of contemporary planning techniques shows an excellent early cardiac safety. Abstract P1355 Figure.