- The purpose of this study was to evaluate the efficacy of platinum-based chemotherapy (PBC) versus conventional non-PBC regimens in a metastatic triple-negative breast cancer (TNBC) setting. We reviewed the electronic patient records of patients with confirmed metastatic TNBC at four major cancer centres in Canada. All patients were allocated into two groups based on type of chemotherapy received (PBC vs. non-PBC) and line of treatment (first-, second-, or third-line). The primary objective of this study was to evaluate the efficacy of PBC in metastatic TNBC in terms of median duration of overall survival (OS) from diagnosis of distant metastatic disease and compare it with the efficacy of conventional non-platinum-based chemotherapy in metastatic TNBC after controlling for known prognostic factors. A total of 153 metastatic TNBC patients were identified, 58 treated with PBC and 95 with non-PBC. The median time in first-line PBC versus non-PBC was not different between the two groups (2 vs. 2 months, p = 0.9), the median time on treatment in second and third-line therapy was longer for the PBC group compared to the conventional treated group (4 vs. 1 months, p = 0.004; 4 vs. 0.5 months, p = 0.004, respectively). Patients who received PBC had a longer OS compared to those managed conventionally (14.5 vs. 10 months, p = 0.041). This study evaluates the survival outcomes in a homogenous group of TNBC metastatic patients treated with or without PBC. Our results confirmed our hypothesis of a better OS among PBC-treated TNBC patients compared to conventionally managed TNBC patients. Currently ongoing Phase III trials assessing the benefit of PBC versus other chemotherapeutic regimens in advanced TNBC will help define the role of these agents for the management of this breast cancer subtype.