Ki-67 Is A Predictive Marker For A Pathological Complete Response To Neoadjuvant Chemotherapy In Breast Cancer:a Meta-analysis

Purpose: A pathological complete response(pCR)after neoadjuvant chemotherapy is a strong indicator of the benefit of therapy and presents an early surrogate for a favorable long-term outcome.It remains unclear whether Ki-67,a marker for tumor proliferation,can function as a predictor of the response to neoadjuvant chemotherapy in breast cancer.The objective of this meta-analysis was to compare the p CR rate and clinical outcomes in breast cancer patients with different Ki-67 labeling indexes(Ki-67 LI)who received neoadjuvant chemotherapy.Methods: Clinical studies were retrieved from three English databases(PubMed,Embase and Clinical Trials),and two Chinese databases(Wanfang and Chinese National Knowledge Infrastructure databases),from their inception to Jul 31,2017.Meta-analysis was performed on pool eligible studies to determine whether Ki-67 LI was associated with the pCR rate and clinical outcomes of breast cancer patients who were treated withneoadjuvant chemotherapy.Pooled analyses were performed using RevMan5.3 software.Results: A total of 36 studies involving 6,793 patients were included in the meta-analysis.Pooled analysis results revealed that patients with high Ki-67 LI exhibited significantly higher pCR rates(OR=3.94,95% CI:3.33-4.67,P<0.001)but poorer relapse-free survival(HR=1.99,95% CI:1.39-2.85,P<0.001)than those with low Ki-67 LI,but there was no significant difference in objective tumor response rate.Conclusion: The meta-analysis reported here demonstrates that pre-therapeutic Ki-67 LI is associated with pCR in breast cancer patients undergoing neoadjuvant chemotherapy.