Dynamic changes in cardiac biomarkers in radiotherapy for oesophageal cancer and their correlations with cardiac radiation dosimetry

Background and purpose: To investigate the dynamic changes in cardiac enzymes, high-sensitivity troponin T (hsTnT), pro-brain natriuretic peptide (pro-BNP) and left ventricular ejection fraction (LVEF) during radiotherapy (RT) and 6 months after RT for oesophageal squamous cell carcinoma (ESCC) in the middle and lower locations and to analyse the correlations between these indicators and cardiac radiation dosimetry parameters. Methods: For 35 patients with ESCC in the middle and lower locations receiving radical concurrent chemoradiotherapy (cCRT), intensity-modulated RT was performed at 1.8 Gy or 2.0 Gy per day, and the totle dose was 50.4 Gy or 60 Gy. Serum creatine kinase (CK), creatine kinase isoenzyme (CK-MB), lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (alpha-HBDH), hs-TnT, pro-BNP and LVEF were measured before, during, and at the end of RT and 1, 3 and 6 months after RT, and correlations of these indicators with mean heart dose (MHD) and heart V5-V50 were analysed. Results: hs-TnT during, at the end and 6 months after RT for oesophageal cancer showed increasing trends, however, LVEF showed a downward trend. pro-BNP showed an increasing trend during RT and gradually returned to normal after RT. CK and CK-MB showed decreasing trends during RT and continued until one month after RT and then gradually returned to normal. Compared with the low-dose group (MHD < 2000 cGy), the high-dose group (MHD >= 2000 cGy) had larger increases in hs-TnT and pro-BNP, a more significant decrease in LVEF, and a longer recovery time for these indicators. MHD and V35 were positively correlated with dynamic changes in hs-TnT. Conclusions: Cardiac injury caused by cCRT for ESCC in the middle and lower locations led to increased hs-TnT and pro-BNP levels and a decrease in LVEF in the early stage of treatment, effects that were more pronounced in the high-dose group. MHD and V35 may be potential indicators to predict the degree of cardiac damage. hs-TnT and pro-BNP are sensitive indicators reflecting cardiac injury in RT for oesophageal cancer. Continuous dynamic monitoring of these markers can provide a reference for cardiac protection in clinical RT.