Paclitaxel-based versus docetaxel-based regimens in metastatic breast cancer: a systematic review and meta-analysis of randomized controlled trials

Docetaxel and paclitaxel show significant clinical activity in metastatic breast cancer (MBC) and have been approved for MBC by the U.S. Food and Drug Administration, but it is still unclear whether a paclitaxel-based regimen improves outcomes over a docetaxel-based regimen in patients with MBC. We therefore performed a meta-analysis of randomized controlled trials to compare the safety and efficacy of these two regimens in MBC.We systematically searched for randomized controlled trials that comparing paclitaxel-based with docetaxel-based regimens in patients with MBC in PubMed (up to January 2012), Embase (1980 to January 2012), and the Cochrane databases (up to January 2012). Abstracts presented at conferences (up to January 2011) were also searched. Data were extracted from the studies by two independent reviewers. The meta-analysis was performed by Stata version 12.0 software (Stata Corporation, College Station, TX, USA).Seven eligible trials involving 1694 patients with MBC were selected. Our results showed that a paclitaxel-based regimen was comparable to a docetaxel-based regimen for MBC patients in terms of OS (HR: 0.87, 95% CI: 0.60-1.27, p = 0.48), PFS (HR: 0.76, 95% CI: 0.58-1.00, p = 0.052), TTP (HR: 1.13, 95% CI: 0.81-1.58, p = 0.46), and ORR (RR: 1.01, 95% CI: 0.88-1.15, p = 0.92), but fewer grade 3 or 4 adverse events including anemia (RR: 0.64, 95% CI: 0.44-0.94, p = 0.023), neutropenia (RR: 0.74, 95% CI: 0.58-0.93, p = 0.011), febrile neutropenia (RR: 0.38, 95% CI: 0.15-0.96, p = 0.041), thrombopenia (RR: 0.62, 95% CI: 0.41-0.96, p = 0.033), mucositis (RR: 0.082, 95% CI: 0.025-0.27, p < 0.001), diarrhea (RR: 0.19, 95% CI: 0.081-0.47, p < 0.001) and fatigue (RR: 0.43, 95% CI: 0.20-0.96, p = 0.039) were observed in the paclitaxel-based regimen. However, limitations of our study needed to be considered when interpreting these results: our study was a meta-analysis of published data, and there was significant heterogeneity among included trials. Potential publication bias might also exist.The present systematic review and meta-analysis demonstrates that both taxane-based regimens have comparable efficacy for patients with MBC, and the paclitaxel-based regimen is associated with less toxicity and better tolerability, especially in older patients and when used in weekly regimens.