Impact of obesity on sentinel lymph node biopsy outcomes and survival in breast cancer patients: A single‐center retrospective study

Abstract Background Sentinel lymph node biopsy (SLNB) is a common choice for axillary surgery in patients with early‐stage breast cancer (BC) who have clinically negative lymph nodes. Most research indicates that obesity is a prognostic factor for BC patients, but studies assessing its association with the rate of positive sentinel lymph nodes (SLN) and the prognosis of patients with early BC undergoing SLNB are limited. Methods Between 2013 and 2016, 7062 early‐stage BC patients from the Shanghai Cancer Center of Fudan University were included. Based on the Chinese Body Mass Index (BMI) classification standards, the patients were divided into three groups as follows: normal weight, overweight, and obese. Propensity score matching analysis was used to balance the baseline characteristics of the participants. Logistic regression analysis was used to determine the association between obesity and positive SLN rate. Cox regression analysis was used to investigate whether obesity was an independent prognostic factor for early‐stage BC patients who had undergone SLNB. Results No significant association was observed between obesity and positive SLN rate in early‐stage BC patients who had undergone SLNB. However, multivariate analysis revealed that compared to patients with normal BMI, the overall survival (hazard ratio (HR) 2.240, 95% confidence interval (CI) 1.27–3.95, p = 0.005) and disease‐free survival (HR 1.750, 95% CI 1.16–2.62, p = 0.007) were poorer in patients with high BMI. Conclusion Obesity is an independent prognostic factor for early‐stage BC patients who undergo SLNB; however, it does not affect the positive SLN rate.