Chemotherapy-related outcomes in triple-negative breast cancer.

Abstract

e12049 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 mainstays of treatment for non-metastatic TNBC. However, anthracyclines are associated with an increased risk of potentially life-threatening adverse effects. We sought to compare survival 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-May 2018 were included in the 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 vs ASRs. Results: 137 patients met inclusion criteria with a median follow-up of 39 months. 21 patients (15%) recurred and 16 (12%) died. Patients treated with ABRs (n = 26, 19%) compared with ASRs (n = 111, 81%) had significantly shorter median EFS (38 months vs not-yet-reached, NYR, p < 0.001), DFS (37 months vs NYR, p < 0.001), and OS (50 months vs NYR, p < 0.001). Though patients in the ABR vs the ASR group were more likely to be node-positive (Odds Radio 3.46, p = 0.006), shorter survival estimates in the ABR group were observed after adjusting for nodal status. 27% of patients (7/26) had an anthracycline added after suboptimal response to an ASR. After adjusting for these patients, the survival findings were similar. 43 patients (31%) received a platinum containing ASR. In the platinum subgroup, ASRs were associated with longer EFS and DFS compared to ABRs, but this effect was not statistically significant in the node-positive group. No cardiac or secondary leukemic events were observed in either group. Conclusions: ABRs were associated with shorter EFS, DFS and OS, even after adjusting for certain high-risk clinical features. Larger studies are needed to identify the role of platinum containing ASRs in patients with early TNBC.