Neoadjuvant Chemotherapy Response in Breast Cancer among Nigerian Women: A Systematic Review and Meta-Analysis (2000-2025).

Background: Neoadjuvant chemotherapy (NACT) is increasingly employed for locally advanced breast cancer in Nigeria, but treatment outcomes remain heterogeneous and often uncertain relative to global standards. Methodology: We systematically reviewed Nigerian studies on NACT outcomes using PubMed, Embase, Scopus, Web of Science, AJOL, and grey literature through September 2025. Eligible studies included women receiving NACT who reported an objective response rate (ORR) or a pathologic complete response (pCR). Quality was assessed using ROBINS-I or RoB-2, and certainty was rated using GRADE. Pooled estimates were generated with random-effects (DerSimonian-Laird) models. Results: = 39%). Excluding a non-standard single-agent trial raised pCR to 21%. The HER2-targeted ARETTA trial achieved pCR = 53%, approximating global benchmarks. Although one comparative study showed lower Nigerian pCR (5% vs 27% U.S.), survival appeared similar among patients completing multimodality therapy (observational finding). Certainty of evidence was rated low-to-moderate (GRADE). Conclusions: NACT in Nigeria achieves consistent clinical downstaging but modest pCR outside HER2-targeted settings. Expanding access to biomarker testing, taxanes, trastuzumab (including biosimilars), and ensuring therapy completion are essential to close the global outcome gap.