Abstract P2-12-22: Neoadjuvant weekly carboplatin and paclitaxel followed by dose dense adriamycin/cyclophosphamide in locally advanced triple negative breast cancer: A single-center real-world experience

Abstract

Abstract Background: Locally advanced triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer comprising 10-20% of new diagnoses each year. Optimization of neoadjuvant therapy is necessary to decrease risk of relapse. Carboplatin has been explored as an addition to standard chemotherapy to increase rates of pathologic complete response (pathCR) and improve disease free (DFS) and overall survival. Studies have shown varying degrees of benefit, however the ideal usage of carboplatin in this setting remains unclear. Methods: A retrospective chart review was conducted at Baylor College of Medicine to examine outcomes of patients receiving carboplatin. 93 patients with TNBC were identified as treated with weekly carboplatin at an AUC of 2 and paclitaxel followed by dose dense adriamycin/cyclophosphamide (ddAC) between 2015 and 2020. Results: The average age at diagnosis was 50 (range 30 - 73). 48 (52%) patients were Hispanic, 27 (29%) were African American. 15 (16%) were BRCA carriers. 39 (42%) patients had clinical Stage II disease, 54 (58%) patients had clinical stage III disease. 66 (71%) patients had T3 or T4 disease. 60 (64%) patients had nodal disease at diagnosis. The pathCR rate for the overall population was 43%, of the patients who did not achieve a pathCR, 9 (18%) had residual cancer burden (RCB) I, 24 (45%) had RCB II, and 20 (37%) had RCB III at the time of surgery. 5-year disease free survival (DFS) after surgery for all patients was 72% (95% CI 60-85%). 5 yr DFS was 64% (95% CI 48-85%) for patients without pathCR compared to 82% (95% CI 67-99%) for patients with pathCR (p=0.3, logrank test). Patients with clinical stage II disease had a pathCR rate of 59%; patients with clinical stage III disease had a pathCR rate of 32%. By tumor stage, T2 patients had a pathCR rate of 52%, T3 patients had a pathCR rate of 47% and T4 patients had a pathCR rate of 6%. By nodal stage, N0 patients had a pathCR rate of 58%, N1 patients had a pathCR rate of 38% and N2 patients had a pathCR rate of 11%. 5-year OS by tumor stage was 68% (95% CI 46-100%) for T2, 85% (95% CI 72-100%) for T3, and 54% (95% CI 30-98%) for T4. 5-year OS by nodal stage was 96% (95% CI 90-100%) for N0, 69% (95% CI 53-89%) for N1, and 83% (95% CI 58-100%) for N2 disease. Adverse events were similar in frequency and severity to prior studies. Conclusion: Our single center data demonstrates that a neoadjuvant regimen of weekly carboplatin/taxol followed by ddAC was safe and efficacious in a high-risk group of primarily minority patients. Despite having more advanced disease compared to patients in randomized trials receiving weekly carboplatin such as GeparSixto, this regimen remained successful in achieving pathCR and low residual disease burden. While a higher burden of disease was consistently associated with a lower rate of complete response across clinical stage, tumor status, and nodal status, this did not entirely correspond with overall survival in our limited patient population. Further studies are needed to determine the ideal patient population for the treatment of carboplatin. Citation Format: Nan Chen, Shaun Bulsara, Susan Hilsenbeck, Julie Nangia. Neoadjuvant weekly carboplatin and paclitaxel followed by dose dense adriamycin/cyclophosphamide in locally advanced triple negative breast cancer: A single-center real-world experience [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-12-22.