Robot-Assisted Partial Nephrectomy of Larger Renal Tumors Successful

Becky McCall

March 23, 2011

March 23, 2010 (Vienna, Austria) — The use of robot-assisted partial nephrectomy (RAPN) for tumors larger than 4 cm is effective and safe, and outcomes are similar to those seen with RAPN for tumors smaller than 4 cm, according to a study presented as a poster here at the European Association of Urology 26th Annual Congress.

However, RAPN for larger, clinical stage T1b tumors is associated with longer warm ischemia times (by 7 minutes, on average), longer operative times, greater blood loss, and a higher rate of collecting system repair than RAPN clinical stage T1a tumors. Even so, none of these factors appear to be associated with renal damage.

Georges-Pascal Haber, MD, PhD, from the Department of Urology at the Cleveland Clinic, Ohio, and colleagues conducted a multiinstitutional analysis of perioperative outcomes of RAPN for clinical stage T1b tumors. Institutions that participated in the study were the Cleveland Clinic; Henry Ford Hospital, Detroit, Michigan; New York University, New York City; and Washington University, St. Louis, Missouri.

Dr. Haber commented on the difficulties associated with the removal of tumors larger than 4 cm: "They are very challenging to remove. At many institutions, radical nephrectomies are being performed, which have unfavorable outcomes on renal function and survival. In recent years, we've been conducting more open partial nephrectomies."

However, he added, open partial nephrectomies require a larger incision, removal of a rib, and a longer time for patient recovery. As a consequence, laparoscopic partial nephrectomy, which is minimally invasive and decreases recovery time, has become more popular. However, laparoscopy requires advanced surgical skills and is a technique that takes a long time to master. "Robots have decreased the learning curve and have opened up the possibility of conducting partial nephrectomy for larger tumors without compromising renal function and recovery time," Dr. Haber told Medscape Medical News.

In this study, RAPN of clinical stage T1b tumors larger than 4 cm (4.1 to 11.0 cm) was compared with RAPN of clinical stage T1a tumors.

The researchers showed that RAPN required a longer warm ischemia time (24 vs 17 minutes; < .001), longer operative time (194 vs 180 minutes; = .017), greater blood loss (200 vs 150 mL; < .001), and a higher rate of collecting system repair (72.2% vs 51.6%).

There was no significant difference in percentage decrease in mean estimated glomerular filtration rate (9% vs 4.5%; = .09), nor was there any difference in postoperative complications between patients who had tumors larger than 4 cm and those who had tumors smaller than 4 cm.

Data on 445 patients who underwent RAPN at the 4 American institutions between 2006 and 2010 were included in this analysis. They were stratified into 2 groups, according to tumor size estimated by radiographic imaging: 83 patients had clinical stage T1b tumors and 362 patients had stage T1a tumors. Mean follow-up was carried out at 10 months, with the longest follow-up taking place at 45 months.

"What matters for the patients is the hospital stay, renal function, [estimated glomerular filtration rate], survival, and cancer control. For these factors, no difference was found whether the tumor was less than 4 cm or greater than 4 cm," Dr. Haber pointed out.

Commenting on the study, Sébastien Crouzet, urologist at Edouard Herriot Hospital, Lyon, France, said: "They found a difference in the warm ischemia time, but as long as it is not over 30 minutes, then permanent damage is less likely to occur. It was only 24 minutes in this study. This means risk to the kidney shouldn't be a problem."

He added that RAPN is a welcome alternative to laparoscopy, because the latter is a very difficult technique, and only highly skilled surgeons usually perform the procedure. "Robots have been used widely for prostate cancer and in some aspects of kidney surgery, but use in tumors is far more recent," Dr. Crouzet pointed out.

"The big advantage with RAPN is that the surgeon recovers all the freedom of movement he or she has in open surgery and, in addition, the optics provide [3-dimensional] vision, which means a surgeon reproduces the field of surgery in [3 dimensions], and can also reproduce any movement he wants with his hands. Surgeons can more easily move from open surgery to robot-assisted surgery, rather than to laparoscopy. As far as the patient is concerned, it means less pain, less scarring, and equivalent oncological results," explained Dr. Crouzet.

In the future, Dr. Haber and his colleagues at participating centers hope to conduct a prospective randomized study to compare this technique with the gold standard of open partial nephrectomy. "This would be our next step; we could then determine if this is to be the new standard of care."

Dr. Haber reports being a consultant to Intuitive Surgical, which manufactures the robots used in the technique described. Dr. Crouzet has disclosed no relevant financial relationships.

European Association of Urology (EAU) 26th Annual Congress. Presented March 9, 2011.

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