Chemotherapy regimen choice and patient outcomes in early-stage triple-negative breast cancer: a retrospective analysis

BACKGROUND: Triple-negative breast cancer (TNBC) is associated with a poor prognosis when compared to hormone receptor–positive breast cancers. Anthracycline-based regimens (ABRs) are mainstay for treatment of non-metastatic TNBC. However, anthracyclines are associated with an increased risk of potentially life-threatening adverse effects. We sought to evaluate outcomes in patients with early TNBC treated with ABRs versus those treated with anthracycline-sparing regimens (ASRs). METHODS: All patients treated for stage I–III TNBC who had undergone curative-intent surgery at a large academic medical center between January 2013 and May 2018 were included in this retrospective study. Event-free survival (EFS) and disease-free survival (DFS) were the primary endpoints, with overall survival (OS) as a secondary endpoint and were defined as per standardized STEEP criteria. Kaplan–Meier, multivariable Cox regression, and log-rank tests were used to define key survival and treatment-related differences between subjects treated with ABRs versus ASRs. RESULTS: One hundred thirty-two patients met inclusion criteria with a median follow-up of 55.9 months. Twenty-seven patients (20%) had disease recurrence and 20 (15%) died. Patients in the ABR group were more likely to have nodal involvement (chi-square p = 0.011). Patients treated with ABRs (n = 26, 20%) compared with ASRs (n = 106, 80%) had significantly shorter median EFS (32.4 months vs not reached (NR), p < 0.001), DFS (26.2 months vs NR, p < 0.001), and OS (49.2 months vs NR, p < 0.001). The shorter survival observed in the ABR group persisted after adjusting for nodal status and on multivariate analysis. Of the 26 ABR-treated patients, 9 (35%) had an anthracycline added after suboptimal response to an ASR. Regardless of reason for anthracycline inclusion, the survival outcomes were similar. No cardiac or secondary leukemic events were observed in either group. CONCLUSION: ABRs were associated with shorter EFS, DFS, and OS, even after adjusting for certain high-risk clinical features.