Efficacy and safety of first-line carboplatin-paclitaxel and carboplatin-gemcitabine in patients with advanced triple-negative breast cancer: a monocentric, retrospective comparison

Background: Platinum-based chemotherapy is widely used in patients with advanced triple-negative breast cancer (TNBC). However, the most effective platinum-based chemotherapy combination in the first-line treatment setting remains unclear. Methods: : We evaluated the efficacy of first-line carboplatin-paclitaxel (CP) or carboplatin-gemcitabine (CG) combinations in advanced TNBC patients treated at “Fondazione IRCCS Istituto Nazionale dei Tumori” between April 2007 and April 2021. CP and CG were compared in terms of progression-free survival (PFS), overall survival (OS) and incidence of adverse events (AEs). Multivariable Cox Models were used to adjust the efficacy of CP vs. CG for clinically relevant covariates. Results: : Of 418 consecutive advanced breast cancer patients receiving carboplatin-based doublet chemotherapy, 88 patients had advanced TNBC and were treated in the first-line setting. Of these, 56 (63.6%) and 32 (36.4%) patients received CP and CG, respectively. Clinically relevant variables were well-balanced in the two treatment cohorts, except for a higher percentage of patients with shorter disease-free interval in the CG group (59.4% vs. 44.6%; p value 0.038). After adjusting for clinically relevant variables, patients receiving CG had significantly better PFS when compared to CP-treated patients [aHR: 0.49 (95%CI: 0.27-0.87), p value 0.014]. Of note, CG was associated with better PFS only among patients previously treated with taxanes in the (neo)adjuvant setting (aHR: 0.39; 95%CI: 0.21-0.75), but not in patients not exposed to taxanes (aHR: 1.20; 95%CI: 0.37-3.88). CG was also independently associated with better OS when compared to CP [aHR: 0.31 (95%CI: 0.15-0.64), p value 0.002]. Overall, grade 3-4 AEs were more common in patients treated with CG than in patients treated with CP (68.8% vs . 21.4%, p value 0.009). Conclusions: : CG and CP are effective and well tolerated first-line platinum doublets in advanced TNBC patients. CG could be more effective than CP in patients previous exposed to taxanes despite worse toxicity profile.