Comparison of extraperitoneal and transperitoneal pelvic lymph node dissection during minimally invasive radical prostatectomy

Background and Purpose: Pelvic lymph node dissection (PLND) during radical prostatectomy (RP) has prognostic and possible therapeutic benefits. We assessed whether an extraperitoneal minimally invasive RP (MiRP) allows for standard-template PLND comparable to transperitoneal MiRP+PLND. Patients and Methods: A retrospective clinicopathologic study of 914 consecutive patients who underwent MiRP (laparoscopic or Da Vinci robot-assisted laparoscopic) with bilateral PLND by one surgeon (CPP) from 2001 to 2010 was performed. Low-risk patients generally received a limited dissection (external iliac nodes) when PLND was performed. Those with intermediate- and high-risk disease generally received a standard PLND (external iliac and obturator nodes). Patients were stratified into groups based on operative approach (extraperitoneal vs transperitoneal) for most analyses. Results: Overall, 192 patients had transperitoneal MiRP+PLND, and 377 had extraperitoneal MiRP+PLND. The extraperitoneal group had higher body mass index (P=0.03), a higher percentage of low-risk (P=0.003), and a lower percentage of intermediate-risk disease (P=0.006). Lymph node yield (LNY) was higher with extraperitoneal PLND overall (6.5 vs 5.3, P=0.003). When stratified by risk category, LNY was greater in the extraperitoneal group for patients with low-risk disease only (6.6 vs 4.9, P=0.008). There was no difference in nodal yield in intermediate/high-risk patients receiving standard PLND by either the transperitoneal or extraperitoneal approach (6.0 vs 5.5, P=0.36 and 8.0 vs 5.8, P=0.14, respectively). Lymph node involvement was rare overall. Estimated blood loss and complication rates were comparable between operative approaches. Conclusion: The extraperitoneal MiRP approach does not compromise the oncologic efficacy or safety of routine PLND.