Effect of neoadjuvant chemotherapy in patients with triple-negative breast cancer: A meta-analysis

The present meta-analysis aimed to evaluate the effect of neoadjuvant chemotherapy on pathological complete response (pCR) and survival rate in patients with triple-negative breast cancer (TNBC). Specific inclusion and exclusion criteria were used to conduct a search of the available databases, in order to find studies performed between January 2006 and January 2014. The bibliographies of the included studies were examined with the same criteria. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group framework was used to evaluate the included studies, and RevMan 5.1 and GRADEprofiler 3.6 were used to analyze the extracted data. A total of 19 studies with 6,180 patients were included. The meta-analysis revealed that the pCR rates in patients with TNBC were significantly higher than those in patients with non-TNBC. The 5-year disease-free survival (DFS) and overall survival (OS) rates were significantly lower in the patients with TNBC compared with those with non-TNBC. Furthermore, these survival rates were significantly higher in the patients with TNBC who achieved a pCR compared with those in the patients who did not achieve a pCR. pCR rates were higher among the patients with TNBC with high Ki-67 expression than among those with low Ki-67 expression. The patients with TNBC exhibited lower survival rates compared with those with non-TNBC, but achieved higher pCR rates. Moreover, those patients achieving a pCR exhibited improved 5-year survival rates, suggesting that the pCR rate could be predictive of survival in patients with TNBC. In addition, high Ki-67 expression may predict the likelihood of a pCR. However, future multicenter randomized controlled trials are required to enhance the quantity and quality of the clinical evidence.