Are Changes in Circulating Tumor Cell (CTC) Count Associated with the Response to Neoadjuvant Chemotherapy in Local Advanced Breast Cancer? A Meta-Analysis

Introduction: Circulating tumor cells (CTCs) represent a biomarker for tumor progression and monitoring therapeutic effects. We evaluated the association between the changes in CTC count and the pathological response to neoadjuvant chemotherapy (NCT) for local advanced breast cancer (LABC) patients. Methods: PubMed, EBSCO, Web of Science, conference proceedings and key trials for the period 1998-2012 were searched. We used the hazard ratio (HR) to evaluate the variation in the number of CTCs to predict the response to NCT in LABC patients. All data from each study were investigated using either fixed-or random-effect models and were analyzed using Stata software. Results: There was no between-study heterogeneity in pathological complete response (pCR) (heterogeneity chi-squared = 0.02 (df = 1), 12 = 0.0%, p = 0.877). Our meta-analysis showed that the change (decrease or increase) in CTC number in LABC patients during NCT was not correlated with pCR (HR = 0.918, 95% confidence interval 0.650-1.295; p = 0.877). Conclusion: The results of the current meta-analysis indicate that there is no association between the decrease of CTC number and pCR after NCT. According to our results, a decrease in the CTC count after NCT in LABC patients did not indicate that they had an improved response to NCT. However, more randomized clinical trials are needed to confirm this conclusion.