Anthracycline-containing versus anthracycline-free carboplatin-based regimens in early-stage triple-negative breast cancer: real-world outcomes.

PURPOSE: Triple‑negative breast cancer (TNBC) is an aggressive disease with poor survival outcomes. With the integration of immunotherapy, the optimal neoadjuvant chemotherapy backbone remains poorly defined. We examined real-world treatment patterns and response rates among patients receiving a carboplatin-based regimen, with or without anthracyclines. METHODS: In this retrospective cohort study, women diagnosed 2012-2024 with stage I-III TNBC who received neoadjuvant carboplatin plus taxane (CbT) or CbT with anthracyclines (AC-CbT) were identified from electronic health records data from 10 sites within the Greater Plains Collaborative network. Registry-recorded physician assessment of pathologic complete response (pCR) was the primary outcome. Multivariable logistic regression evaluated whether adding anthracyclines to carboplatin-based treatment was associated with pCR. RESULTS: Among 878 patients with TNBC, 41.2% received CbT and 58.8% received AC-CbT. Overall, 46% received pembrolizumab, 11.7% in the CbT group and 66.3% in the AC-CbT group. On univariate analysis, pCR rates did not differ between the CbT and AC-CbT groups (47.2% vs. 51.9%, OR = 1.21, 95%CI 0.92-1.58), among patients who underwent surgery. In multivariate adjusted analyses, AC-CbT was not associated with higher odds of pCR (aOR = 1.05, 95%CI 0.69-1.59), among patients who underwent surgery. Other patient characteristics associated with pCR included pembrolizumab use, higher-grade disease, lower stage, and age at diagnosis (40-49 versus 60+). Use of carboplatin-containing regimens increased substantially over time. CONCLUSION: In this real-world cohort, addition of anthracycline to carboplatin-containing regimen was not associated with an improvement in pCR rates. These findings suggest clinical equipoise regarding anthracycline omission in early-stage TNBC, to be validated in prospective trials. Additional work evaluating adherence, toxicity, and long-term outcomes is needed.