Weekly vs Every-3-Week Carboplatin with Weekly Paclitaxel in Neoadjuvant Chemotherapy for Triple-Negative Breast Cancer: A Retrospective Analysis

Background: Adding carboplatin to weekly paclitaxel as part of neoadjuvant chemotherapy (NACT) for stage II-III triple negative breast cancer (TNBC) has been shown to significantly increase the pathologic complete response (pCR) rate. Hematologic toxicities associated with every 3-week dosing of carboplatin have led some oncologists to explore weekly dosing as an alternative, but there are little published data comparing the two dosing schedules. Methods: We performed a retrospective analysis of patients who received paclitaxel and carboplatin, usually followed by AC, as initial NACT for TNBC at two academic cancer centers between 2008 and 2018 for whom pathologic results and post-operative follow-up were available. We recorded pCR, defined as ypT0/isN0, treatment delivery and disease-free survival, censored as of the patient's last follow-up visit. Results: A total of 76 patients were identified (median age 49 years). A total of 47 received weekly carboplatin, of whom 83% received at least 11 of 12 planned doses, and 29 received every 3-week carboplatin, of whom 90% received all 4 planned doses. pCR rates were similar, 53% with weekly and 55% with every 3-week carboplatin dosing. At median follow-up of 18 months (range <1- 118), 93% of patients who achieved pCR were alive and free from recurrence, compared to 74% of those who did not. Conclusion: pCR rates were similar between patients receiving weekly or every 3-week carboplatin and were similar to those reported in prior trials with carboplatin. These data suggest that providers can choose either weekly or every 3-week carboplatin dosing without compromising the likelihood of achieving pCR.