Standard versus limited pelvic lymph node dissection for prostate cancer in patients with a predicted probability of nodal metastasis greater than 1%

PURPOSE: We determined the yield of standard vs limited pelvic lymphadenectomy in patients with a predicted risk of lymph node metastasis greater than 1% according to the Partin tables predicted probability of pathological stage. We also determined the feasibility of laparoscopic standard pelvic lymph node dissection. MATERIALS AND METHODS: Of 1,269 patients with clinically localized prostate cancer undergoing radical prostatectomy, 648 had a Partin's table predicted probability of lymph node invasion greater than 1%. Of the 648 patients 177 underwent limited pelvic lymph node dissection performed laparoscopically (group 1), and 471 underwent standard pelvic lymph node dissection performed open (367) or laparoscopically (104) (group 2). Templates of limited pelvic lymph node dissection included the external iliac lymph nodes whereas standard pelvic lymph node dissection included the external iliac, obturator and hypogastric lymph nodes. Multivariate logistic regression analyses were performed to compare the node positivity rate between groups 1 and 2. RESULTS: On multivariate logistic regression analysis controlling for prostate specific antigen, biopsy Gleason sum, clinical stage and surgical approach, the odds of node positivity were 7.15-fold higher (95% CI 2.49-20.5, p<0.001) for standard vs limited pelvic lymph node dissection. The median (mean) number of nodes retrieved was 9 (10) and 14 (15) after limited and standard pelvic lymph node dissection, respectively (p<0.001). A similar impact was observed in patients treated laparoscopically with standard vs limited pelvic lymph node dissection (odds ratio 15.6, 95% CI 3.7-66.4, p<0.001). CONCLUSIONS: Standard lymph node dissection yields positive nodes more frequently and retrieves a higher total nodal count than the often performed pelvic lymph node dissection limited to the external iliac nodes. Standard pelvic lymph node dissection is feasible through a transperitoneal laparoscopic approach.