Cardiotoxicity of Immune Checkpoint Inhibitors with Anthracycline Chemotherapy in Triple-Negative Breast Cancer

Background/Aim: The addition of an immune-checkpoint inhibitor (ICI) to chemotherapy improves outcomes in both early-stage and metastatic triple-negative breast cancer (TNBC). However, ICIs are associated with immune-related adverse events (irAEs), such as cardiotoxicity, raising concerns for patients receiving both anthracyclines and ICIs. We sought to determine if combining anthracycline and ICI in TNBC is associated with greater cardiotoxicity than anthracycline alone. Methods: A retrospective cohort study was conducted at a large academic center. Two cohorts were analyzed: anthracycline plus ICI and anthracycline alone. Demographics, comorbidities, medications, cardiac imaging, and outcomes were reviewed. Time to adverse cardiac events were compared. Results: A total of 382 patients were included: 297 received anthracyclines without ICI, and 85 received both. There were no major differences in baseline characteristics. The rate of acute cardiac events was 3.4% in the anthracycline-alone cohort and 3.5% in the anthracycline-plus-ICI cohort (p > 0.99) over a median of 1232 days of follow up (median of 1336 days in the anthracycline only group; median of 704 days in the ICI group). No significant differences in acute heart failure, acute coronary syndrome, myocarditis, or pericardial effusion were observed. Kaplan–Meier analysis showed no significant difference in cardiac event-free survival (p = 0.60). Furthermore, there was no significant difference in time to cardiac events between the two groups following competing risk analysis when accounting for both prior coronary artery disease (HR = 1.32, 95% CI: [0.42, 4.14], p = 0.64) and age (HR = 1.64, 95% CI: [0.52, 5.19], p = 0.40). Conclusions: This single-institution analysis did not identify a significant increase in cardiotoxicity with the addition of an ICI to anthracycline therapy in patients with TNBC. Active surveillance for cardiotoxicities should continue in patients receiving ICI in addition to anthracycline therapy.