Authors: Nan Chen, Shaun Bulsara, Susan G. Hilsenbeck, Mothaffar F. Rimawi, Julie R. Nangia
Published: 2021-06-02
DOI: 10.1200/jco.2021.39.15_suppl.e12629
Source: Full article
e12629 Background: Locally advanced triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer comprising 10-15% 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, and the ideal usage of carboplatin remains unclear. Methods: A retrospective chart review was conducted in the Harris County Health System to examine outcomes of patients receiving carboplatin. 71 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 31 – 73). 44 (62%) patients were Hispanic, 19 (27%) were African American. 11 (15%) were BRCA carriers. 30 (42%) patients had clinical Stage II disease, 41 (58%) patients had clinical stage III disease. 53 (75%) patients had T3 or T4 disease. 48 (68%) patients had nodal disease at diagnosis. The pathCR rate for the overall population was 43%, of the patients who did not achieve a pathCR, 6 (15%) had residual cancer burden (RCB) I, 21 (51%) had RCB II, and 14 (34%) had RCB III at the time of surgery. 5 year disease free survival (DFS) after surgery for all patients was 70% (95% CI 56-86%). 5 yr DFS was 63% (95% CI 45-88%) for patients without pathCR compared to 79% (95% CI 62-100%) for patients with pathCR (p = 0.3, logrank test). 61% of patients had between 3 – 5 adverse events. 30 (42%) patients required a treatment delay. 12 (17%) patients required treatment discontinuation. The most common serious adverse event was neutropenia affecting 9 (12%) patients. Conclusions: Our single center data in a safety net clinical setting 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, our patients still had similar response rates. Additionally, our data supports the continued use of pathCR as a valid indicator of disease free and overall survival.