Pathologic Complete Response and Its Impact on Breast Cancer Recurrence and Patient’s Survival after Neoadjuvant Therapy: A Comprehensive Meta-Analysis

Objective. Earlier research has illustrated prognostic significance of pathologic complete response (pCR) in neoadjuvant therapy (NAT) for breast cancer, whereas correlation between treatment after achieving pCR and survival improvement remains underexplored. We attempted to measure the relation between pCR achieved after NAT and breast cancer recurrence or patient’s survival. Methods. We searched PubMed, EMBASE, Web of Science, and The Cochrane Library databases to find relevant articles from their inception to November 2020. According to eligibility criteria, studies were selected and basic data were extracted. The primary endpoint was the correlation between pCR achieved after NAT and event-free survival (EFS) or overall survival (OS). The results were obtained by directly extracting specific information from the literature or estimating individual data by survival curves on DigitizeIt software, presented with HR and 95% CI. All data were processed on Stata 14.0 software. Results. Among 4338 articles, there were 25 eligible articles involving 8767 patients. The EFS of patients achieved pCR after NAT improved obviously ( HR = 0.27 ; 95% CI, 0.24-0.31), especially in triple negative ( HR = 0.17 ; 95% CI, 0.12-0.24) and HER2 positive ( HR = 0.24 ; 95% CI, 0.20-0.30) breast cancer patients. As such, pCR after NAT was implicated in significantly increased OS ( HR = 0.32 ; 95% CI, 0.27–0.37). Conclusion. Achieving pCR after NAT was notably related to the improvement of EFS and OS, especially for patients with triple-negative and HER2-positive breast cancer. pCR can be a surrogate indicator for outcome of breast cancer patients after NAT, as well as a predictor of treatment efficacy after NAT. Besides, well-designed studies are still warranted for confirmation.