Anthracycline-free platinum-based neoadjuvant chemotherapy in operable triple-negative breast cancer: Interim analysis of pathologic complete response rates and predictors of response.

34 Background: Neoadjuvant chemotherapy (NACT) remains the cornerstone of treatment for operable triple-negative breast cancer (TNBC), with pathologic complete response (pCR) regarded as a key surrogate marker of long-term outcomes. Although platinum-based regimens are associated with higher pCR rates, the optimal composition of neoadjuvant therapy, including the role of anthracyclines, has not been definitively established. In this context, data on the feasibility and efficacy of anthracycline-free platinum-based NACT in routine clinical practice remain limited. Methods: This prospective single-center interim analysis included 52 patients with stage II–III TNBC who received anthracycline-free platinum-based NACT consisting of carboplatin combined with weekly paclitaxel. The primary endpoint was pCR (ypT0/is ypN0). Treatment delivery and clinicopathologic predictors of pCR were assessed using univariate logistic regression analysis. Results: Pathologic complete response was achieved in 30 of 52 patients, corresponding to a pCR rate of 57.7%. The presence of a germline BRCA1/2 mutation was significantly associated with a higher likelihood of achieving pCR (OR 6.67; 95% CI 1.31–33.92; p = 0.022). A higher Ki-67 proliferation index was also associated with increased probability of pCR (OR 1.07 per 1% increase; 95% CI 1.02–1.12; p = 0.006). Stromal tumor-infiltrating lymphocytes (TILs) ≥20% demonstrated a trend toward higher pCR rates but did not reach statistical significance. Chemotherapy dose reductions occurred in 42.3% of patients, including carboplatin (40.4%) and paclitaxel (28.8%). Median dose reductions among affected patients were 15% and 25%, respectively. Neither chemotherapy dose reductions nor treatment delays were associated with a decreased likelihood of achieving pCR. Conclusions: Anthracycline-free platinum-based NACT demonstrated a clinically meaningful pCR rate in operable TNBC with preserved treatment delivery despite frequent dose modifications. Germline BRCA1/2 mutations and high Ki-67 were associated with an increased probability of pCR, whereas the predictive value of TILs remains limited and requires validation in larger cohorts. These findings support the feasibility of anthracycline-free platinum-based regimens and may inform patient selection.