Extended pelvic lymph node dissection during robotic prostatectomy: antegrade versus retrograde technique

Background: Robot-assisted radical prostatectomy (RARP) with extended lymphadenectomy (ePLND) is the gold standard for surgical treatment of prostate cancer (PCa). Recently, the en-bloc ePLND has been proposed but no studies reported on the standardization of the technique. The aim of the study is to describe different standardized en-bloc ePLND, the antegrade and the retrograde ePLND, and to compare their surgical and oncological outcomes. Materials & methods: From January 2018 to September 2019, all patients subjected to RARP plus ePLND by one single surgeon were enrolled. ePLND was performed in a retrograde fashion by starting laterally to the medial umbilical ligament from the internal inguinal ring proceeding towards the ureter, or in an antegrade way by starting from the ureter at its crossing with the common iliac artery and proceeding towards the femoral canal. Patients' demographic data, clinical and surgical data were collected. Each en-bloc ePLND was categorized as "efficient" or "inefficient" by the operator, as surrogate of surgeon's satisfaction. Results: Antegrade and retrograde ePLND were performed in 41/105 (group A) and 64/105 (group R) patients, respectively. The two groups (A vs R) had similar median (IQR) number of lymph nodes retrieved [20 (16.25-31.5) vs 19 (15-26.25); p = 0.18], ePLND time [33.5 (29.5-38.5) min vs 33.5 (26.5-37.5) min; p = 0.4] and post-operative complications [8/41 (19.5%) vs 9/64 (14.1%); p = 0.61]. In group A, 3/41 (7.3%) clinically significant lymphoceles were reported, while 1/64 (1.6%) in group R (p = 0.3). 33/41 (80.5%) and 28/64 (44%) procedures were scored as efficient 59 in group A and R, respectively (p = 0.01). On multivariate regression, only BMI (B = 0.93; 95% CI 0.29-1.56; p = 0.005) was associated with a longer ePLND time. Conclusions: The study indicates that antegrade and retrograde en-bloc extended pelvic lymph node dissection (ePLND) have comparable surgical and oncologic outcomes, supporting the importance of standardizing the procedure rather than focusing on the direction. Although both techniques aligned with current evidence regarding lymph node invasion and complications, the antegrade approach was subjectively perceived as safer due to early isolation of critical anatomical landmarks. Encouragement for the use of en-bloc ePLND, regardless of direction, is emphasized to improve prostate cancer staging accuracy and procedural standardization.