Early Effects of Modern Radiotherapy for Lung Cancer on Endothelial Damage and Myocardial Fibrosis: A Prospective Single-Center Study

Abstract

Radiotherapy (RT) may have a cardiotoxic effect on the heart and cardiovascular system. Postulated mechanisms mediating these complications include vascular endothelium damage and myocardial fibrosis. The aim of our study was to assess endothelial damage and myocardial fibrosis in the early period after RT on the basis of cardiac biomarkers and in relation to the radiation dose applied to individual heart structures in patients treated for non-small-cell lung cancer. This single-center prospective study included consecutive patients with lung cancer (LC) who were referred for treatment with radiochemotherapy (study group) or chemotherapy (control group). The study protocol included performing an echocardiographic examination, a standard ECG examination, and collecting blood samples for laboratory tests before starting treatment for lung cancer in the first week after completing RT (after four cycles of chemotherapy in the control group) and after 12 weeks from the end of treatment. The study included 23 patients in the study group and 20 patients in the control group. Compared to the baseline values, there was a significant increase in total cholesterol concentration in the study group immediately after the end of RT, which persisted for three months after the end of therapy. After taking into account the use of statins in the analysis, it was found that an increase in total cholesterol concentration after oncological treatment was observed only among patients who did not use statins. Taking into account the assessment of myocardial fibrosis markers, there were no significant changes in the concentration of matrix metallopeptidase 9 (MMP-9) and tissue inhibitors of metalloproteinases 1 (TIMP-1) in the study group. In patients treated with radiochemotherapy, there was a significant increase in the concentration of intercellular adhesion molecule 1 (ICAM-1) immediately after RT, when compared to the baseline. After taking into account the use of statins, an increase in ICAM-1 concentration immediately after RT was observed only in patients who did not use statins. There was also a significant correlation between the radiation dose received by the left anterior descending coronary artery (LAD) and left circumferential coronary artery, and vascular cell adhesion protein 1 (VCAM-1) concentration measured at three months after the end of RT. Immediately after completion of radiotherapy, a significant increase in the level of ICAM-1 is observed indicating endothelial damage. The radiation dose to coronary arteries should be minimized, as it correlates with the concentration of VCAM-1. The use of statins may prevent the increase in total cholesterol and ICAM-1 concentration after irradiation for lung cancer; however, further studies designed for this specific purpose are necessary to confirm the effectiveness of statins in this area.