Background: High body mass index (BMI) is regarded as a poor prognostic factor in breast cancer (BC). However, its association with pathological complete response (pCR) and survival after neoadjuvant chemotherapy (NAC) remains controversial.
Objective: We wanted to assess the prognostic impact of BMI in this setting.
Methods: Single-center, retrospective review of 314 BC patients undergoing NAC from 2010 to 2018. Patients were categorized as underweight/normal weight (UW/NW) (BMI < 25) or overweight/obese (OW/OB) (BMI ≥ 25). The relationship between BMI and other traditional clinical-pathological prognostic variables with the pCR rate was investigated using logistic regression analysis. The effect on event-free survival (EFS) and overall survival (OS) was estimated by the Cox proportional hazards regression analysis.
Results: One hundred and twenty-two patients were UW/NW while 192 were OW/OB. Multivariate analysis revealed that hormonal receptors negative, HER2 positive, and clinical tumor stage (cT) 1-2 were independent predictor factors for pCR. Multivariate analysis confirmed tumor grade G3 and lack of pCR as independent adverse prognostic factors for EFS, while factors associated with worse OS were cT3-4, hormone receptors negative, and lack of pCR. Non-significant differences in pCR, EFS, or OS were observed between the two baseline BMI categories.
Conclusions: In our experience, BMI is not associated with pCR, EFS, or OS in BC patients receiving NAC. Achieving pCR is the most consistent factor associated with EFS and OS. Prospective and well-designed studies taking into account other important biological and anthropometric factors are needed to determine the exact role of BMI in this setting.
Keywords: Body mass index; breast cancer; neoadjuvant chemotherapy; obesity; pathological complete response; prognosis; survival.