Cardiac toxic effect of radiation therapy in patients receiving adjuvant trastuzumab treatment, as examined by LVEF of echocardiography: an experimental research

Radiation in breast cancer patients may result in cardiovascular disease affecting the pericardium, myocardium, and cardiac valves. OBJECTIVE: This study aimed to evaluate the cardiotoxic consequences of radiotherapy in breast cancer patients who underwent adjuvant trastuzumab treatment by echocardiographic left ventricular ejection fraction (LVEF) measurement. METHODS: In this retrospective study patients treated with postoperative breast irradiation with adjuvant trastuzumab were examined in terms of LVEF. Eithy five patients with age of 31–76 referred to the radiotherapy department of 5 Azar Hospital of Gorgan, Iran between years 2013 and 2020 were analyzed. Patients were divided into two left sided and right sided breast groups. Patients are routinely assessed every 3 months by echocardiocraphgy. LVEF values was measured at intervals of 3, 6, and 12 months after treatment onset. RESULT: On the left side, the average of LVEF immediately decreased after treatment, compared to before treatment (∆ LVEF= 0.021), which shows the impact of trastuzumab. The LVEF average 3 months after treatment onset showed a significant decrease (∆ LVEF= 0.043) indicating a synergistic effect of trastuzumab and radiotherapy. LVEF average 6 months and 1 year after treatment onset showed a decrease but not significant (∆ LVEF= 0.009 and 0.013, respectively).In the right breast LVEF average immediately 3 months after treatment showed a significant decrease (∆ LVEF= 0.011 and 0.057, respectively). Nevertheless, LVEF average does not show a significant decrease after 6 months and 1 year after treatment in the right side group (∆ LVEF= 0.0002 and 0.018, respectively). CONCLUSION: Our results showed LVEF changes within one year following treatment in left sided breast cancer was more than right side , but the difference was not significant ,which may be due to the short period of our study based on the protocol of our department. More changes in the left side must be due to placing of the heart in the path of radiation. The study showed that LVEF may be an indicative measure for assessing radiation and adjuvant treatment effects on cardiac function.