BMI and Pathologic Complete Response to Neoadjuvant Chemotherapy in Breast Cancer: A Study and Meta-Analysis.

INTRODUCTION: There is only limited data from clinical practice on the relevance of body mass index (BMI) on pathologic complete response (pCR) following neoadjuvant chemotherapy (NAC) in patients with breast cancer (BC). PATIENTS AND METHODS: The impact of BMI on pCR and survival outcome was examined in 324 patients with primary non-metastatic BC. An additional meta-analysis was performed on the current data and relevant previously published studies in clinical practice. RESULTS: Multivariable regression analysis identified lymph vascular invasion (odds ratio [OR], 0.05; 95% confidence interval [CI], 0.01-0.18; P = .0000), grading 3 (OR, 3.12; 95% CI, 1.59-6.12; P = .0009), and HER2/neu status (OR, 4.76; 95% CI, 1.86-12.18; P = .011) as independent factors for pCR after NAC. There was no association between pCR and continuous or categorical BMI. Various additional subgroup analyses of molecular BC subtypes (triple-negative, luminal-like, HER2-luminal, HER2-like) and BMI also showed no association. These findings were confirmed by the meta-analysis. Except for one subgroup analysis in which overweight and obese patients were combined as one group, no association between BMI and pCR as well as survival outcome was found. CONCLUSIONS: BMI was not established as a relevant clinical factor. Only lymph vascular invasion, grading 3, luminal-like, and HER2/like BC subtype showed predictive and prognostic impact in patients with BC receiving NAC.