Predictive value of high-sensitive Troponin T Rise within the upper reference limit in breast cancer

Background The utility of elevated troponin (Tn) as a marker of cardiotoxicity is well-established in cancer patients. We investigated the role of high-sensitive cardiac troponin T (hsTnT) increase in patients with Breast Cancer (BC) below the upper limit of normal (ULN). hsTnT assays accurately quantify very low plasma Tn concentrations and enable early detection of cardiomyocyte injury before left ventricle ejection fraction (LVEF) drop. The increase of hsTnT below the ULN in response to chemotherapy has not previously been studied. Methods This was an open-label pilot study. Female patients with newly diagnosed BC scheduled to receive systemic cancer treatment were recruited. Blood sampling and echocardiography were performed before treatment, and then at 3 and 6 Months. hsTnT concentrations were measured using the Elecsys TnT hs assay (Roche Diagnostics). The limit of blank and 99th percentile cutoff values for the hsTnT assay were 3 and 14 ng/L. We calculated the rise of hsTnT by the difference (%) between its baseline level and during follow-up in the 6 Months in each patient. Results Among 81 eligible subjects, we excluded 4 patients before the start of treatment and 17 patients during the follow-up with values for the hsTnT >14 ng/L. Finally, 60 women with a median age of 48.6±1.3 years were included in the study. The median baseline hsTnT concentration was 5.5 ± 1.4 ng/L. During 6 Months hsTnT increased in all patients up to 10 % - 305 % from baseline, by an average of 94.2%. LV EF was normal at baseline (61,9±3,3%) and decreased significantly (56.3±7.0%) compared to value before cancer treatment (p<0.045). We correlated hsTnT rise with a drop LV EF ≥10 % from its baseline level. Given the AUC, hsTnT has a good predictive value for LV dysfunction, 0.78 (p=0.05), 95% CI (0.67-0.90). The increase of hsТnТ >81% was determined as the optimal threshold value for the detection of early biochemical cardiotoxicity. Conclusion It was found that using a cutoff of <14 ng/L of hsTnT levels are valuable for early biochemical cardiotoxicity risk stratification during cancer treatment. We conclude that BC patients with increased hsTnT plasma concentration >81% from baseline value should be considered as a high risk patients for cardiotoxicity and need more precise cardiac monitoring and early preventive medical intervention strategies.