Robotics in Urologic Oncology: Partial Nephrectomy for Kidney Cancer

Robotic surgery is the latest evolution in laparoscopic surgery. Traditional laparoscopic surgery was and is performed with rigid instruments, a two-dimensional view with the surgeon at the patient's bedside and an assistant controlling the camera (or view) of the operation. Robotic surgery makes use of a three-dimensional, dual-camera system; instruments that mimic natural hand motions leading to improved ergonomics, and while the surgeon sits at a console away from the patient, he or she has full control of the camera and view of the operation. The robotic systems used today are termed "master-slave" systems where the robot transforms human movements into scaled robotic movements, but the robotic instruments cannot function independently or autonomously.

The most widely-used robotic system is the daVinci system by Intuitive Surgical. This system was first cleared by the FDA in 1997 for surgical assistance, for radical prostatectomy in 2001 and broad urological surgery in 2005. There are currently over 2,000 daVinci units in use in the United States and nearly 1,000 additional units worldwide. Urology and urologic oncology as specialties represent a major proportion of the utilization of robotic surgery. For many diseases and operations, robotic technology has improved perioperative and long-term outcomes – for other operations the benefit is marginal at best. In this series of blog entries, we will review the utilization and impact of robotic technology on a number of urologic oncology disease states.

The first blog in this series will focus on kidney cancer and the use of robotic partial nephrectomy.

 

THE HISTORY OF LAPAROSCOPIC NEPHRECTOMY AND PARTIAL NEPHRECTOMY

The first laparoscopic radical nephrectomy was performed in 1991 by Dr. Clayman and colleagues at the Washington University School of Medicine, St Louis.[1] Unlike appendectomy (appendix removal) and cholecystectomy (gallbladder removal) in general surgery, the adoption of laparoscopic nephrectomy was slow in the US with only 30% of nephrectomies being performed laparoscopically by 2005.[2] In comparison, 70% of gallbladders were removed laparoscopically 15 years after the first laparoscopic cholecystectomy. During the same time period, partial nephrectomy (PN, or removal of just a kidney tumor and the surrounding normal kidney tissue) was historically underutilized in the US. In the 1990's and early 2000's, only approximately 10% of kidney surgeries were PN – and most of these were performed at large, academic, urban and teaching hospitals.[3] While the rates oif both laparoscopy and PN increased during the 2000's, the majority of PN were performed through an open incision, once again in large urban and teaching hospitals.[4]

 
In the late 2000's, a number of national and worldwide trends changed the way kidney surgery was performed. First, robotic technology was taking off – the daVinci system was approved for radical prostatectomy in 2001 and over the next decade hospitals all over the US were acquiring robots. As the number of robotic prostatectomies and surgeries increased nationwide, surgeons became more comfortable with robotic technology and began looking for more uses. In addition, in 2009, the AUA (American Urological Association) released the "Guidelines for the Management of the Clinical Stage 1 Renal Mass." The Guideline states that "Nephron-sparing surgery should be considered in all patients with a clinical T1 renal mass as an overriding principle," and within a year of releasing the Guidelines, the utilization of PN increased from 27% to 32% nationwide.[5]

 
Data from Johns Hopkins and the State of Maryland indicate that the rate of PN increased from 9% to 27% from 2000 to 2010. The proportion of open PN decreased by 1/3^rd and robotic and other minimally-invasive PN increased to nearly 60% of all PN. Importantly, after 2008 (a time period which robotic technologies were widely disseminated), being treated at a university hospital was no longer a predictor of PN – PN was finally becoming widespread!![6] 

The increasing using of robotic and minimally-invasive partial
nephrectomy in the State of Maryland. From Patel et al. [6]

This local trend was reflected in national data, indicating modest increases in open PN (8%) but dramatic increases in robotic PN (45%) in the National Inpatient Sample (a large all-payer inpatient care database cataloguing over 7 million inpatient hospitalizations).[7]

 

COMPARATIVE OUTCOMES FOR ROBOTIC PARTIAL NEPHRECTOMY: 

DO THE DATA SUPPORT THIS TREND?

In general, the increasing use of robotic PN is supported by data and represents one of the true "success stories" for robotic surgery. Robotic surgery is beneficial to patients undergoing PN as the wristed robotic instruments and three-dimensional views facilitate better and faster removal of tumors and reconstruction of the kidney.  The video below is a representative example of a robotic PN: the artery is temporarily clamped to facilitate a bloodless resection and reconstruction (ischemia time), the tumor is resected and the kidney is reconstructed.

In a systematic review of eight studies comparing robotic PN to open PN, robotic PN was associated with:

• Longer operative time (+40.89 minutes ; p = 0.002)
• Lower perioperative complication rate (19.3% for RPN and 29.5% for OPN)
  • Odds ratio: 0.53; 95%CI, 0.42–0.67; p<0.001
• Shorter hospital stay (−2.78 days; p<0.00001)
• Less estimated blood loss (−106.83mL; p = 0.003)

There was no difference observed in transfusions, conversion to radical nephrectomy, ischemia time, estimated GFR change (kidney function), surgical margin status, or overall cost.[8]
Comparing robotic to laparoscopic PN in a systematic review of 12 studies and over 700 patients, demonstrated no difference in operative times, estimated blood loss, conversion rates, length of hospital stay, complications, or positive margins between the surgeries. In fact, the only notable difference was that robotic PN was associated with less warm ischemic time (quicker removal of the tumor and reconstruction of the kidney). It should be noted that laparoscopic surgery was performed by fewer, but expert surgeons while robotic PN was performed by a greater variety of surgeons of varying experience level.[9]

When comparing our data at Johns Hopkins, we found that robotic PN was associated with improved operative parameters (operative time, blood loss, ischemia time) and fewer serious complications.[10] In addition, we determined that the learning curve for robotic PN was much quicker than laparoscopic surgery – about 25 patients.[11]

While long-term oncologic data is lacking, surrogate oncologic measure (i.e. surgical margin status) and short-term recurrence and survival data indicate that robotic PN is equivalent to open and laparoscopic surgery with regards to oncology outcomes, and likely superior with regard to perioperative outcomes.

 

SUMMARY

• The emergence of robotic technology dramatically changed the management of kidney cancer in the United States, with more patients undergoing partial nephrectomy now than ever before.
• The comparative data demonstrates improved outcomes for many peri-operative and surrogate oncologic outcomes. Longer-term data will likely confirm robotic PN as the standard-of-care for small renal masses requiring treatment.

 

 

This blog was adapted from a lecture titled "Robotics in Urologic Oncology," given by Phillip M. Pierorazio, MD, Assistant Professor of Urology and Oncology, at the Emirates Oncology Conference, 2014 in Abu Dhabi.

 

 

1. Clayman et al. Laparoscopic Nephrectomy. N Engl J Med 1991; 324:1370-1371May 9, 1991. http://www.nejm.org/doi/full/10.1056/NEJM199105093241918
2. Miller, D. C. et al. JAMA 2006;295:2480-2482
3. Hollenbeck, Urology, Volume 67, Issue 2, 2006, 254 - 259
4. Patel et al., J Urol, Volume 187, Issue 3, 2012, 816 - 821
5. Bjurlin et al., Urology, Volume 82, Issue 6, 2013, 1283 - 1290
6. Patel et al., J Urol, 2013 Apr;189(4):1229-35.
7. Ghani et al., J Urol, Volume 191, Issue 4, 2014, 907 - 913
8. Wu etal. PLoS One. 2014; 9(4): e94878.
9. Aboumarzouka etal. Eur Urol. 2012 Dec;62(6):1023-33.
10. Mullins etal. Urology. 2012 Aug;80(2):316-21.
11. Pierorazio et al., Urology, 78 (2011), p. 813