Body Mass Index and prostatic-specific antigen are predictors of prostate cancer metastases in patients undergoing robot-assisted radical prostatectomy and extended pelvic lymph node dissection

BACKGROUND: The aim of this study was to investigate the risk factors contributing to multiple lymph node invasion (LNI) in patients with prostate cancer (PCa) undergoing extended pelvic lymph node dissection (ePLND) during robot assisted radical prostatectomy (RARP). METHODS: A total of 211 patients who underwent RARP and ePNLD from June 2013 to March 2017 were classified according to lymph node status in the surgical specimen (absent, single or multiple). Risk factors of LNI were evaluated by the multinomial logistic regression model. A receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to assess the efficacy of factors and model evaluation. RESULTS: On multivariate analysis, the risk of multiple LNI, was independently increased by Body Mass Index (BMI) (odds ratio [OR] 1.194; P=0.026) and prostate-specific antigen (PSA) (OR=1.089; P=0.014) when compared to patients without LNI. ROC curves indicated that both BMI (AUC=0.702) and PSA (AUC=0.732) had fair discrimination power. For each unit of increase in PSA, the odds of multiple lymph node invasion increased by 8.9% and for each unit increase of BMI, the odds of multiple LNI increased by 19.4%. CONCLUSIONS: The risk of multiple LNI was independently predicted by PSA and BMI with fair discrimination power.