Risk factors of positive surgical margins after robot-assisted radical prostatectomy in high-volume center: results in 732 cases

The aim of the study was to evaluate clinical, pathological and peri-operative factors associated with the risk of positive surgical margins (PSM) after robot-assisted radical prostatectomy (RARP) in a high-volume center. The study is a retrospective analysis of prospectively collected data. We excluded cases who were under androgen deprivation or had prior treatments. The population included negative cases (control group) and PSM subjects (study groups). The logistic regression model assessed the independent association of factors with the risk of PSM. From January 2013 to December 2017, 732 patients underwent RARP. Extended pelvic lymph node dissection was performed in 342 cases (46.7%). Overall, 192 cases (26.3%) had PSM. Independent factors associated with the risk of focal PSM were body mass index (odds ratio, OR = 0.936; p = 0.021), percentage of biopsy-positive cores (BPC; OR = 1.012; p = 0.004), pathological extracapsular extension (OR = 2.702; p < 0.0001), seminal vesicle invasion (OR = 2.889; p < 0.0001) and high-volume surgeon (OR = 0.607; p = 0.006). In high-volume centers, features related to host, tumor biology and surgeon are independent factors associated with the risk of PSM after RARP, which are decreased by the high-volume surgeon. The inverse association between BMI and PSM risk needs further clinical research. These issues should be discussed when counseling patients.