Platinum-based chemotherapy in triple-negative breast cancer.

Abstract

1090 Background: There is increasing evidence that DNA repair defects characteristic of BRCA1-related cancers and triple negative breast cancer (TNBC) confer sensitivity to certain chemotherapeutic agents, such as platinums. However, prospective and retrospective studies comparing the efficacy of these agents versus conventional treatment in TNBC are lacking. The aim of this study was to evaluate the efficacy of platinum-based chemotherapy (PBC) in metastatic TNBC in terms of median duration of treatment and overall-survival (OS) and compare it to patients treated with conventional chemotherapy. Methods: We performed a retrospective chart review of patients with metastatic TNBC who received PBC from January 2007 to June 2010 treated at the Sunnybrook Odette Cancer Center. A case-control study was designed, with 3 controls per case matched by age, comprising metastatic TNBC treated with conventional agents. Results: A total of 116 patients were analyzed: 29 treated with PBC and 87 managed with conventional treatment. Median age at diagnosis was 47 years and distant disease-free interval was 27 months (m) for both groups. Patients treated with PBC had more sites of disease (100% vs. 70%, p<0.0001) and a worse performance status (ECOG 2 21% vs. 6%, p=0.034), respectively. Of the 29 patients treated with PBC, 79% received a combination regimen, most commonly weekly cisplatin and gemcitabine in 62% of patients. The median number of cycles delivered was 4 (2-11). 31% received PBC as first-line treatment, 35% as second-line, 28% as third-line and 7% as fifth-line. Only 2 patients discontinued PBC secondary to toxicity. The median time on treatment in first, second and third-line therapy was longer for the PBC group (5 vs. 2 m, p=0.225; 3 vs. 2 m, p=0.063; and 4 vs. 1 m, p=0.009). Patients treated with PBC had a longer OS compared to those managed conventionally (18 vs. 13 m, p=0.025). Conclusions: PBC appears to improve clinical outcomes in patients with metastatic TNBC compared to those treated with conventional chemotherapy regimens. Although this is a retrospective study with its obvious limitations, it adds to the growing body of literature, suggesting the benefit of PBC in TNBC. Prospective trials are needed to confirm this benefit.