ObjectiveTo systematically review the efficacy and safety of CDK4/6 inhibitors combined with endocrine therapy for advanced breast cancer.MethodsPubMed, EMBase, The Cochrane Library, CNKI, WanFang Data and VIP databases were electronically searched to collect randomized controlled trials (RCTs) of CDK4/6 inhibitors combined with endocrine therapy for advanced breast cancer from inception to October 13th, 2017. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 4 RCTs involving 2 524 patients were included. The results of meta-analysis showed that: compared with placebo combined with endocrine therapy, CDK4/6 inhibitors combined with endocrine therapy could improve the median progression free survival rate (RR=0.53, 95%CI 0.47 to 0.60, P<0.000 01) and the objective response rate (RR=1.67, 95%CI 1.47 to 1.91,P<0.000 01). While there was no statistical difference in clinical benefit rate (RR=0.59, 95%CI 0.75 to 1.19,P=0.64). In terms of adverse reactions, CDK4/6 inhibitors combined with endocrine therapy had higher rates of neutropenia (RR=49.76, 95%CI 26.85 to 90.21, P<0.000 01), leukopenia (RR=48.69, 95%CI 18.74 to 133.61,P<0.000 01), fatigue (RR=3.11, 95%CI 1.37 to 7.08,P=0.007) and anemia (RR=2.96, 95%CI 1.61 to 5.42, P=0.000 3). There were no significant differences between two groups in nausea, diarrhea and decreased appetite.ConclusionCDK4/6 inhibitors combined with endocrine therapy for the patients with advanced breast cancer can improve median progression free survival and objective response rate, while increase the incidence of adverse events such as neutropenia, leukopenia, fatigue and anemia. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify above conclusion.
