The da Vinci robot has greater dexterity than a human. (CBC)

Less-invasive keyhole surgery for prostate cancer may mean a higher risk for lasting incontinence and impotence compared to traditional surgery, a new U.S. study suggests.

The results add to confusion around prostate cancer treatments, which sometimes lead to urinary and sexual problems. It's not clear that either kind of surgery is superior to radiation alone or watchful waiting, which means simply monitoring the prostate for changes.

Laparoscopic, or keyhole, surgery is increasingly chosen by men having a cancerous prostate removed. And often it involves the highly marketed da Vinci robotics system. Da Vinci's popularity has been rising even though there has never been a rigorous head-to-head comparison between it and standard surgery.

"There's been a rapid adoption of this relatively new technique," said the study's lead author, Dr. Jim Hu of Brigham and Women's Hospital in Boston.

For the study, appearing in Wednesday's Journal of the American Medical Association, researchers analyzed Medicare data for nearly 9,000 prostate cancer patients who had surgical treatment from 2003-07. Of those, 1,938 patients had minimally invasive surgery and 6,899 patients had standard surgery. The data did not indicate how many of the less invasive cases involved robotics.

The patients who had keyhole surgery left the hospital in two days, rather than three, on average. They also had lower rates of blood transfusions, breathing problems and internal scarring.

'The take-home message for men is they need to dig deeper than simply the message they might be getting from planted stories from device manufacturers or radio ads or billboards.'— Dr. Jim Hu

There was no difference in the rate of additional cancer therapy down the road, suggesting the two techniques were about the same for cancer control.

But the men who had keyhole surgery were more likely to report complications in the first 30 days after surgery involving genital and urinary function. About five per cent of the minimally invasive surgery patients vs. about two per cent of the standard surgery patients had these complications. And after 18 months, they had more incontinence and erectile dysfunction.

"The take-home message for men is they need to dig deeper than simply the message they might be getting from planted stories from device manufacturers or radio ads or billboards," Hu said.

In laparoscopic surgery, small incisions are made and the doctor uses a tiny camera and instruments for the operation. When robotics is used for this, the doctor sits at a console and manipulates similar instruments attached to robotic arms that work on the patient.

From 2001-06, use of the da Vinci system — the only robot available for this operation — rose from one per cent to 40 per cent of all radical prostatectomies. During that time, the stock price of da Vinci's maker, Sunnyvale, California-based Intuitive Surgical Inc., increased 11-fold.

To compete for patients, more hospitals are buying robotic systems and advertising faster recovery times. More doctors are taking the two-day training to learn Intuitive's da Vinci Surgical System.

Learning curve for surgeons

But many doctors perform too few robot-assisted surgeries to get good at it, Hu said, and that could explain the lasting problems that showed up in the study. Previous research has shown doctors who perform the most surgeries get the best results.

Hu had his own learning curve. He's now done more than 700 robotic prostate surgeries, but "it took several hundred cases before I thought I was doing really well in preserving erectile function and continence," he said.

Dr. Steve Freedland of Duke University School of Medicine in Durham, North Carolina, said he doubts the findings will dampen the enthusiasm for robotic surgery — he termed it "mass hysteria over new technology" — because surgeons will claim better-than-average results when they talk to men considering their options.

Freedland, who does prostate surgery, said the results just reinforce his decision to stick with traditional, open surgery.

Surgeries lumped together

"One of the reasons why health care in this country is extremely expensive is because it's assumed that what's newest must be best," Freedland said.

The researchers found that the less-invasive surgery was more popular among more affluent, highly educated men. So it might be that those patients are more likely to seek help for urinary and sexual problems compared to men who had traditional surgery, said Dr. Ashutosh Tewari, director of the Prostate Cancer Institute at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

Tewari, who receives research funding from Intuitive Surgical and had no role in the study, faulted the research for lumping all minimally invasive surgeries together, both robotic and those using older laparoscopic techniques.

Ryan Rhodes, a spokesman for Intuitive Surgical, said there have been more than 800 previous studies on robot-assisted prostate surgery. "The overwhelming majority of these show superior results," both for cancer treatment and urinary continence and sexual function, Rhodes said in an email.

Dr. Greg Zagaja of University of Chicago Medical Center, who does similar research but wasn't involved in the new study, said the Medicare billing codes don't necessarily represent the surgical outcomes. He noted there wasn't a difference in the rate of procedures for treating incontinence and sexual dysfunction between the two groups.

Zagaja said the best advice for men is to ask how many robot-assisted surgeries a doctor has done.