The impact of body mass index on the treatment response to neoadjuvant chemotherapy in patients with breast cancer: A systematic review and meta-analysis

Objective: Many studies have highlighted that elevated body mass index (BMI) not only correlates with an elevated likelihood of developing breast cancer (BC) but may also influence patients’ responsiveness to therapeutic regimens and long-term survival outcomes. The impact of BMI on therapeutic response to neoadjuvant chemotherapy (NAC) in patients with BC remains inconclusive. This study seeks to evaluate the effect of BMI on treatment response in the BC population undergoing NAC via a meta-analysis, thereby providing evidence-based support for clinical decision-making. Methods: PubMed, Embase, Web of Science, and the Cochrane Library were thoroughly searched until July 29, 2024. Eligible studies were selected as per predefined eligibility criteria. Data extraction and quality assessment were executed via the Newcastle-Ottawa Scale (NOS). Statistical analyses were enabled by R 4.4.1 and Stata 17. Results: Fifteen studies encompassing 15,235 patients were incorporated. The meta-analysis revealed that in contrast to patients with a normal or low BMI, those who were overweight or obese had a significantly reduced pathlological complete response (pCR) rate (OR: 0.79, p = 0.040). The underweight cohort demonstrated a higher pCR rate in comparison to those with normal BMI (OR: 1.56, p=0.015). Moreover, overweight and obese cohorts displayed a lower pCR rate in contrast to those having normal BMI (OR: 0.83, p < 0.0001). Conclusion: This study indicates that overweight and obese patients tend to exhibit a reduced pCR, highlighting the need for standardized BMI definitions. Future well-designed prospective studies are necessitated to validate these observations.