The Value of Troponin T Level Change During Chemoradiation in Esophageal Cancer Patients

Abstract

Cardiac adverse events are common in esophageal cancer patients who received chemoradiation (CRT). However, reliable marker is lacking to predict these cardiac events. Troponin T (TnT) is a marker of myocardial necrosis, which is widely used in diagnosis of acute coronary syndromes. The relationship between TnT level change during CRT and cardiac injury is unknown. We hypothesized that the TnT level change during CRT is associated with acute cardiac adverse events and long-term survival outcomes. We retrospectively reviewed 113 esophageal cancer patients who received definitive or neoadjuvant CRT from 2010-2016. All patients consented on a prospective blood collection protocol where samples are drawn at baseline before, once during, at the end of CRT, and at each follow up timepoints. Irradiation dose parameters for the whole heart and each chamber were recorded from the treatment plan. TnT levels were quantified using the Elecsys® TnT-high sensitive assay (Roche Diagnostic). TnT level change was defined as CRT end level divided by baseline level. Logistic regression was used to evaluate the correlation between TnT change and acute cardiac adverse events. Kaplan-Meier method was used to compare survival outcomes in different TnT level change groups. The median TnT level gradually increased from baseline, to mid treatment course, and at the end of CRT: 6.27, 8.56, and 10.63 pg/ml, respectively. The median TnT level change was 1.48 (IQR, 1.12-2.01). For the whole heart, left ventricle (LV), right ventricle (RV), and right atrium (RA), the dose distribution was different between IMRT and proton: IMRT mainly contributed to low dose level (<30Gy), while in high dose regions (>40Gy), proton using passive scattering approach had significantly higher dose than IMRT. The TnT level change was strongly correlated to LV and RV dose percentage from V5 to V50 in proton patients (p<0.01), but not in IMRT patients. Male, lower BMI and lower tumor location were associated with higher TnT increase, while TnT level change could not predict acute cardiac adverse events during CRT or postoperative cardiac complications. There was no significant correlation of TnT levels and survival outcomes. There was significant correlation of TnT levels and cardiac dose distribution in proton patients that was not seen in IMRT patients. Whether TnT level alterations with treatment could correlate with late cardiac events specifically in proton patients requires longer term follow up.