358P - Major adverse cardiovascular event outcomes of adjuvant taxane + anthracycline versus taxane-based chemotherapy in older adults with triple-negative breast cancer: A SEER-Medicare study

Background

Triple-negative breast cancer (TNBC) is regarded as relatively more aggressive compared to other subtypes of breast cancer with characteristic metastatic patterns and poor prognosis. The standard of care for TNBC has historically been anthracycline and taxane-based chemotherapy (ATAX). Despite its effectiveness, anthracyclines carry a small but important risk of cardiotoxicity, which is a concern in older women. The purpose of this study was to evaluate major adverse cardiovascular events in older women with TNBC.

Methods

Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we identified 2,215 women with TNBC diagnosed at age > 65 between 2010-2015. We compared patient and clinical characteristics according to adjuvant chemotherapy regimen (ATAX versus TAX). Logistic regression was performed to estimate the odds ratios (OR) and 95% confidence intervals (CIs), Kaplan Meier survival curves were generated to estimate three-year overall survival (OS) and cancer specific survival (CSS). Cox proportional hazards models were used to analyze OS and CSS while controlling for patient and tumor characteristics. MACE was defined as acute myocardial infarction, heart failure, potentially fatal arrhythmia, and cerebral vascular incidence. Few patients experienced a cardiac death and therefore this was excluded in the analysis.

Results

Of the 2,215 patients in our cohort, a majority of patients 1334 (60.26%) received TAX compared to ATAX 881 (39.78%). Patients who received ATAX were not more likely to experience cardiac outcomes such as acute myocardial infarction (OR 1.10, 95% CI [0.66, 1.82], p=0.724), heart failure (OR 0.73, 95% CI [0.52, 1.05], p=0.09), CVA (OR 0.76, 95% CI [0.45, 1.29], p=0.31), or potentially fatal arrhythmia (OR 0.66, 95% CI [0.29, 1.50], p=0.32) when controlling for traditional risk factors. Among patients who experienced a cardiac outcome, there was no difference in OS or CSS in patients who received TAX vs ATAX (HR 1.18, 95% CI [0.46-2.98], p=0.74 and HR 1.39, 95% CI [0.38 – 5.11] p=0.62).

Conclusions

Among older women with TNBC, receipt of adjuvant chemotherapy with ATAX was not associated with increased risk of adverse cardiac outcomes. For those who experienced a cardiac event, there was no difference in survival amongst those who received TAX compared to ATAX.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Women’s Cancer Developmental Therapeutics Program, University of Colorado Cancer Center.

Disclosure

All authors have declared no conflicts of interest.