Retzius Sparing Robotic Assisted Radical Prostatectomy vs. Conventional Robotic Assisted Radical Prostatectomy: A Systematic Review and Meta-analysis - Beyond the Abstract

Robotic Assisted Laparoscopic Radical Prostatectomy (RALP) as the surgical intervention of choice for localised prostate cancer has led to the continued refinement and evolution of the technique in an attempt to improve oncological and functional outcomes. The Retzius space, named after the Swedish anatomist Anders Retzius (1796-1860) is the retropubic space within the preperitoneal area, behind the transversalis fascia and in front of peritoneum that harbours important vessels and nerves indicated within the urinary continence mechanism. Conventional RALP (Con-RALP) requires accessing this space, potentially disrupting these vital anatomical structures contributing to urinary continence.

In 2010, Galfano et al. described Retzius Sparing Robotic Assisted Laparoscopic Radical Prostatectomy (RS-RALP) through the Douglas space, consequently maintaining the integrity of structures involved in the continence mechanism.1 The purported benefits of the Retzius sparing approach were the early recovery of continence and erectile function. However, there have been concerns raised regarding high surgical positive margin rates with RS-RALP.2 

Our review and meta-analysis critically appraises the existing literature to compare oncological and functional outcomes between Con-RALP and RS-RALP. Our review was performed in accordance with The Cochrane Guidelines and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). PubMed/MEDLINE and Cochrane Central Register of Controlled Trials - CENTRAL (in Cochrane Library - Issue 1, 2018) databases were searched. The GRADE approach was used to assess quality of evidence.

We found that RS-RALP was associated with better early continence rates (≤1 month) (RR1.72, 95% CI 1.27, 2.32, p-0.0005) and at 3 months (RR1.39, 95% CI 1.03, 1.88, p-0.03). Based on the evidence from this review, RS-RALP does confer early continence recovery benefit. Furthermore, continence beyond six months is similar between the two cohorts on statistical grounds; however, the RS-RALP cohort consistently has a higher proportion of continent patients during individual time frames, which is likely to have some clinical relevance. Apart from improving the quality of life of a patient, early and superior continence with RS-RALP is likely to have a positive economic impact on an individual patient and global healthcare services. With the earlier recovery of incontinence and probable need for a lower number of pads, individual cost per case is likely to reduce with a RS-RALP. Additionally, with the lower proportion of patients being incontinent with RS-RALP the number of patients proceeding to incontinence corrective surgery is also likely to reduce costs further.

RS-RALP did not alter T2 PSM rates (RR 1.67, 95% CI 0.91, 3.06, p-0.10) and T3 PSM rates (RR 1.08, 95% CI 0.68, 1.70, p=0.75). Also, short term Biochemical Free Survival appears to be similar between the 2 approaches. We also found a trend towards lower positive surgical margins with Con-RALP, but this was not statistically significantly different from RS-RALP rates. Interestingly, our analyses demonstrated a trend towards relatively higher PSM rates with RS-RALP cohort for T2 cases (16.3% vs. 9.3%) than T3 cases (39% vs. 34.5%). This is similar to other studies that have also shown PSM differences between T2 and T3 disease, even between differing surgical modalities (open, laparoscopic and robotic prostatectomy).3 Thus, postulating that T3 PSM is predominantly a function of tumour biology and T2 PSM is more related to surgeon and technique. It is more likely that patients with positive margins and high-risk pathology will be considered for adjuvant/salvage radiotherapy. It is therefore important that this cohort of patients achieve early continence to ensure timely postoperative radiotherapy, and hence RS-RARP may offer a further advantage in this regard. While most authors have thus focused on developing RS-RARP in low and intermediate prostate cancer, its role in optimizing early continence for those high-risk patients needing postoperative radiotherapy might be highly valuable.

The main limitation of our review is the non-randomised nature of the majority of the included studies, which is reflected in the quality of evidence by GRADE Classification. Furthermore, it is impossible to standardise for heterogeneous techniques and expertise by individual surgeons in the anterior approach. Most RALP surgeons are better familiar with the anterior technique that may contribute to greater learning curve effects in the RS-RALP cohort; thus, continence benefits of RS-RARP are likely underestimated herein. We have attempted to address some of these limitations by using bespoke risk of bias assessment for the non-randomised studies

RS-RALP appears to have earlier continence recovery compared to Con-RALP which doesn’t come at a significant oncologic cost. There was a trend towards higher PSM rates with RS-RALP, though not statistically significant. This trend was less pronounced with T3 disease. The longer-term oncological outcomes and erectile function recovery rates of the approach remain unclear. The learning curves of RS-RALP will have to be defined in order to ensure wide-spread applicability of the approach.


Written by: Ankur Mukherjee, BMedSci, MBChB, MRCS, Department of Urology, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, United Kingdom; Prasanna Sooriakumaran, MD, PhD, FRCSUrol, FEBUB, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom; Bhavan P Rai, MBBS, MRCS, MSc, FRCS(Urol), RCSEng Senior Fellowship in Robotic Surgery, Department of Urology, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, United Kingdom.

References:
1. Galfano A, Ascione A, Grimaldi S, Petralia G, Strada E, Bocciardi AM. A New Anatomic Approach for Robot-Assisted Laparoscopic Prostatectomy: A Feasibility Study for Completely Intrafascial Surgery. European Urology 2010 September 2010;58(3):457-461.
2. Stonier T, Simson N, Davis J, Challacombe B. Retzius-sparing robot-assisted radical prostatectomy (RS-RARP) vs standard RARP: it's time for critical appraisal. BJU Int 2018 Jun 29
3. Tewari A, Sooriakumaran P, Bloch DA, Seshadri-Kreaden U, Hebert AE, Wiklund P. Positive Surgical Margin and Perioperative Complication Rates of Primary Surgical Treatments for Prostate Cancer: A Systematic Review and Meta-Analysis Comparing Retropubic, Laparoscopic, and Robotic Prostatectomy. European Urology 2012 July 2012;62(1):1-15

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