Predictors of Lymph Node Invasion in Patients with Clinically Localized Prostate Cancer Who Undergo Radical Prostatectomy and Extended Pelvic Lymph Node Dissection: The Role of Obesity

Abstract

Objective: In patients with intermediate- and high-risk localized prostate cancer (PCa), improving the detection of occult lymph node metastases could play a pivotal role for therapeutic counseling and planning. The recent literature shows that several clinical factors may be related to PCa aggressiveness. The aim of this study is to investigate the potential associations between clinical factors and the risk of multiple lymph node invasion (LNI) in patients with intermediate- and high-risk localized PCa (cT1/2, cN0, and ISUP grading group >2 and/or prostate-specific antigen (PSA) >10 ng/mL) who underwent radical prostatectomy (RP) and extended pelvic lymph node dissection (ePLND). Materials and Methods: In a period ranging from January 2014 to December 2018, 880 consecutive patients underwent RP with ePLND for PCa. Among these, 481 met the inclusion criteria and were selected. Data were prospectively collected within an institutional dataset and retrospectively analyzed. Age (years), body mass index (BMI; kg/m²), PSA (ng/mL), prostate volume (mL), and biopsy positive cores (BPC; %) were recorded for each case. BMI and BPC were considered continuous and categorical variables, respectively. The logistic regression models evaluated the association of clinical factors with the risk of nodal metastases. Results: LNI was detected in 73/418 patients (15.2%) of whom 40/418 (8.3%) harbored multiple LNI (median 2, IQR: 3–4). On multivariate analysis, BMI was independently associated with the risk of multiple LNI in the pathological specimen when compared with patients without LNI (OR = 1.147; p = 0.018), as well as the percentage of biopsy positive cores (OR = 1.028; p < 0.0001) and European Association of Urology high-risk class (OR = 5.486; p < 0.0001). BMI was the only predictor of multiple LNI when compared with patients with 1 positive node (OR = 1.189, p = 0.027). Conclusions: In intermediate- and high-risk localized PCa, BMI was an independent predictor of the risk of multiple lymph node metastases. The inclusion of BMI within LNI risk calculators could be helpful, and a detailed counseling in obese patients should be required.