Pathologic complete response and breast cancer survival post-neoadjuvant chemotherapy: A systematic review and meta-analysis of real-world data
Marcelo Antonini, André Mattar, Thaynan Piontkovsky Pereira, Ludmila Lemos Oliveira, Marina Diógenes Teixeira, Andressa Gonçalves Amorim, Odair Ferraro, Larissa Oliveira, Marcellus do Nascimento Moreira Ramos, Francisco Pimentel Cavalcante, Felipe Zerwes, Marcelo Madeira, Leonardo Ribeiro Soares, Eduardo Camargo Millen, Antônio Luiz Frasson, Fabrício Palermo Brenelli, Gil Facina, Rogério Fenile, Renata Arakelian, Ruffo Freitas‐Júnior, Marcela Bonalumi dos Santos, Henrique Lima Couto, Luíz Henrique Gebrim
Abstract
Breast cancer is a leading cause of cancer-related mortality worldwide, and neoadjuvant chemotherapy (NAC) plays a pivotal role in its management by reducing tumor size, enabling breast-conserving surgery, and improving survival outcomes. Achieving pathologic complete response (pCR) is strongly associated with better overall survival (OS) and disease-free survival (DFS), particularly in aggressive subtypes such as triple-negative (TNBC) and HER2-positive breast cancers. This systematic review and meta-analysis evaluated the correlation between pCR, OS, and DFS in breast cancer patients treated with NAC, focusing exclusively on real-world data (RWD). A comprehensive search with PRISMA guidelines of major databases from 1999 to 2024 identified 22 retrospective studies comprising 12,115 patients. Hazard ratios (HRs) and confidence intervals (CIs) were pooled using random-effects models, and heterogeneity was assessed using the I 2 statistic. pCR was achieved in 20.9% of patients, with higher rates in HER2-positive (44.4%) and TNBC (31.3%) subtypes. Achieving pCR was associated with a 30% improvement in OS (HR: 1.30; 95% CI: 1.28–1.33) and a 29% improvement in DFS (HR: 1.29; 95% CI: 1.24–1.32). Among TNBC patients, pCR correlated with a 51% increase in DFS (HR: 1.51; 95% CI: 1.19–1.93). Significant heterogeneity (I 2 = 96%) was observed across studies. These findings highlight the importance of pCR as a robust predictor of improved survival outcomes in breast cancer, particularly in TNBC and HER2-positive subtypes, and underscore the need for strategies to increase pCR rates to enhance long-term survival and disease control.