EAU 2019: Impact of Surgical Factors on Robotic Partial Nephrectomy Outcomes: Comprehensive Systematic Review and Meta-Analysis

Barcelona, Spain (UroToday.com) In this 25-minute presentation, Drs. Cacciamani and Larcher worked together to provide a discussion of Dr. Cacciamani’s paper entitled “Impact of Surgical Factors on Robotic Partial Nephrectomy Outcomes: Comprehensive Systematic Review and Meta-Analysis,” which was published last summer in the Journal of Urology.1 It was a comprehensive paper focused on multiple surgical factors that may impact robotic partial nephrectomy outcomes.

They highlighted the fact that it reviewed 12,106 papers and ultimately included 270 manuscripts, including 44,891 patients and 7 different surgical approaches and techniques. As a result of all the questions they addressed, they had 856 Forrest Plots as outputs – and had to develop a novel way of presenting the data succinctly. Hence, they created a “Summary Forrest Plot” – this indicates the final outcome of the meta-analysis for all the outcomes assessed in any given population for any given question. 

All the individual Forrest plots addressed the question of robotic vs. open partial nephrectomy which is are collated into a single summary Forrest plot, looking at each of the different outcomes.

The manuscript, which was a meta-analysis and systematic review, was done according to PRISMA, AHRQ standards, using Oxford Level of Evidence criteria and was registered on PROSPERO. The key questions asked included:

  • How Robotic Partial Nephrectomy (RPN) compares with other surgical approaches
  • How RPN techniques compare to each other
  • How tumor and patient characteristics impact perioperative outcomes

Due to time constraints, they only got through the first two in this presentation, but the paper addresses all these questions. The breakdown of the literature search and paper inclusion is below:

EAU2019 UroToday Surgical Factors on Robotic Partial Nephrectomy

1) Open vs. Robotic Partial Nephrectomy: 33 papers, 9106 patients assessed

Not accounting for tumor complexity (RENAL nephrometry score): Open Partial was superior in: OR time, warm ischemia time
RPN was superior in: EBL, transfusion rate, Post-op complications, Length of Stay (LOS), Readmission rates, eGFR increase, Recurrence rates, and Overall mortality
There was no difference in: conversion to radical nephrectomy, positive surgical margins, cancer-specific mortality or intra-op complications
When accounting for nephrometry score (and also when looking at those studies with only nephrometry score >= 7):
Open Partial was superior in: None
RPN was superior in: EBL, transfusion rate, Post-op complications, Length of Stay (LOS), eGFR increase
There was no difference in: OR time, warm ischemia time, conversion to radical nephrectomy, positive surgical margins, cancer specific mortality or intra-op complications, Recurrence rates, and Overall mortality

Based on this, the benefit of a faster operative time and warm ischemia time with open nephrectomy disappears with increasing complexity. And, as robotic PN becomes more common, even this may disappear. There were no major differences in oncologic outcomes – and robotic PN was not inferior to open partial nephrectomy.

Dr. Larcher weighed in here. His own group recently looked at RPN vs. Open Partial Nephrectomy (OPN) in complex renal masses (published after the systematic review was completed). In this study (Larcher et al. EU Oncology 2019), RPN was associated with lower complication rates that OPN for masses of larger size, higher PADUA scores and lower eGFR.

His other comment is that meta-analyses cannot account for factors that aren’t included in the studies that make it up – such as a number of synchronous masses, rate of cN1 or cM1 disease, and rate of patients with prior RCC. These all affect the decision to proceed with one technique or another (likely favoring RPN), but cannot be assessed.

Lastly, he notes that as RPN has only become a significantly used technique in the past 10 years or so, the follow-up is significantly shorter for RPN patients that OPN patients – and that is reflected by many of the studies included in the meta-analysis. This introduces a source of bias that must be addressed.

2) Laparoscopic vs. Robotic Partial Nephrectomy: 51 papers, 8113 patients assessed

Not accounting for tumor complexity (RENAL nephrometry score):
Laparoscopic Partial was superior in: None
RPN was superior in: warm ischemia time, OR time, conversion to radical nephrectomy, conversion to open, transfusion rate, intra- and Post-op complications, eGFR decrease, positive surgical margin rates, and Overall mortality
There was no difference in: EBL, OR time, post-op complications, readmission rates, cancer-specific mortality, recurrence rates
When accounting for nephrometry score (and also when looking at those studies with only nephrometry score >= 7):
Open Partial was superior in: None
RPN was superior in: OR time, warm ischemia time, conversion to radical nephrectomy, LOS
There was no difference in: EBL, transfusion rates, intra-op and post-op complications, eGFR decrease, PSM and recurrence rates

Generally, these results favored RPN over laparoscopic PN.

Dr. Larcher weighed in, noting the lack of strength in these studies. There are twice as many studies for this question – but less patients that the OPN vs. RPN debate. His other point here is the surgical experience required for laparoscopic and robotic partial nephrectomy (demonstrated in Larcher & Mottrie et al. EU) – lower ischemia time and less complications associated with higher surgical experience/volume. Unfortunately, this is not able to be captured in a meta-analysis.

3) Transperitoneal vs. Retroperitoneal PN: 5 papers and 819 patients eligible for this comparison.
Transperitoneal was superior to Retroperitoneal in the following outcomes: None
Retroperitoneal was superior to Transperitoneal in the following outcomes: OR time and EBL

There was no difference between the two in the following: Transfusion rates, conversion to open, conversion to radical nephrectomy, intra-op and post-op complications, LOS, overall mortality, recurrence rates and positive surgical margins

However, as Dr. Larcher commented on, there is no evaluation (due to it not being regularly reported) of tumor location of outcomes from both approaches – yet this plays a major role in the decision to do one vs. the other, in my mind.

Due to time, they essentially had to wrap up here. However, some take-home points from their discussion and the paper itself are:

  • Considering available data from the entire contemporary English language literature, RPN provides mostly superior, but more importantly, at minimum an equivalent outcomes to OPN across various outcomes
  • Evidence of superiority of RPN over LPN is equally compelling
  • Off-clamp, selective clamping, and early hilar unclamping control techniques are safe and feasible approaches for RPN with similar outcomes to on-clamp RPN
  • Minimizing global renal ischemia time may provide superior renal function preservation – but higher quality data is necessary
  • Host factors impact RPN outcomes
  • Tumor size and complexity as well as patient characteristics correlative with perioperative outcomes
  • Patients with comorbidities such as older age, abnormal BMI, CKD and prior abdominal surgery should be selected carefully

Major limitations of the study include:

  • Almost impossible to evaluate the real impact of surgeon expertise on reported results
  • This study did not compare the amount of preserved parenchyma between the groups
  • Overall suboptimal level of evidence of included studies (no RCTs)
  • While multiple sensitivity analyses were done, it is impossible to adjust for everything!


Presented by: 
Giovanni Cacciamani, MD, Assistant Professor of Research Urology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States,
Alessandro Larcher, MD, Università Vita-Salute San Raffaele, Milano, Italy Milan Italy


Written by: Thenappan Chandrasekar, MD (Clinical Instructor, Thomas Jefferson University) (twitter: @tchandra_uromd, @TjuUrology) at the 34th European Association of Urology (EAU 2019) #EAU19, conference in Barcelona, Spain from March 15-19, 2019.

References:
1. Cacciamani GE, Medina LG, Gill T, Abreu A, Sotelo R, Artibani W, Gill IS. Impact of Surgical Factors on Robotic Partial Nephrectomy Outcomes: Comprehensive Systematic Review and Meta-Analysis. J Urol. 2018 Aug;200(2):258-274. doi: 10.1016/j.juro.2017.12.086. Epub 2018 Mar 24.

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