High body mass index predicts multiple prostate cancer lymph node metastases after radical prostatectomy and extended pelvic lymph node dissection

Our aim is to evaluate the association between body mass index (BMI) and preoperative total testosterone (TT) levels with the risk of single and multiple metastatic lymph node invasion (LNI) in prostate cancer patients undergoing radical prostatectomy and extended pelvic lymph node dissection. Preoperative BMI, basal levels of TT, and prostate-specific antigen (PSA) were evaluated in 361 consecutive patients undergoing radical prostatectomy with extended pelvic lymph node dissection between 2014 and 2017. Patients were grouped into either nonmetastatic, one, or more than one metastatic lymph node invasion groups. The association among clinical factors and LNI was evaluated. LNI was detected in 52 (14.4%) patients: 28 (7.8%) cases had one metastatic node and 24 (6.6%) had more than one metastatic node. In the overall study population, BMI correlated inversely with TT (r= -0.256; P < 0.0001). In patients without metastases, BMI inversely correlated with TT (r = -0.282; P < 0.0001). In patients with metastasis, this correlation was lost. In the overall study population, BMI (odds ratio [OR]= 1.268; P=0.005) was the only independent clinical factor associated with the risk of multiple metastatic LNI compared to cases with one metastatic node. In the nonmetastatic group, TT was lower in patients with BMI >28 kg m(-2) (P< 0.0001). In patients with any LNI, this association was lost (P= 0.232). The median number of positive nodes was higher in patients with BMI >28 kg m(-2) (P= 0.048). In our study, overweight and obese patients had a higher risk of harboring multiple prostate cancer lymph node metastases and lower TT levels when compared to patients with normal BMI.