New research from the US suggests that while radical prostatectomy by minimally invasive procedures, including robot-assisted, may shorten the time patients spend in hospital and decrease hospital complications, they may also result in a higher rate of longer term complications such as incontinence and erectile dysfunction.

The study was the work of Dr Jim C Hu, from the Division of Urologic Surgery and the Center for Surgery and Public Health at Brigham and Women’s Hospital, Boston, and colleagues, and is published in the 14 October issue of JAMA.

Use of minimally invasive radical prostatectomy (MIRP), and robot-assisted in particular, has risen steeply: from 1 per cent of all radical prostatectomies in 2001 to 40 per cent in 2006, wrote the authors, adding that the rapid rise has taken place despite there being limited data on outcomes and the costs being greater compared with open retropubic radical prostatectomy or RRP.

RRP is a more conventional operation where a large incision is made in the abdomen to remove the prostate gland, which sits in the pelvis just behind the pubic bone. MIRP involves several small incisions in the abdomen through which instruments are inserted and one through which the prostate is removed, which is why the patient can often leave hospital sooner and is less likely to need a blood transfusion.

Robot-assisted MIRP includes high-tech computerized equipment that costs millions of dollars. The surgeon does not work on the patient directly, but uses joysticks like in a video game to manipulate the instruments in the patient by viewing them on a computer screen.

In their article Hu and colleagues suggest that:

“Widespread direct-to-consumer advertising and marketed benefits of robotic-assisted MIRP in the United States may promote publication bias against studies that detail challenges and suboptimal outcomes early in the MIRP learning curve.”

“Until comparative effectiveness of robotic-assisted MIRP can be demonstrated, open RRP, with a 20-year lead time for dissemination of surgical technique relative to MIRP, remains the gold standard surgical therapy for localized prostate cancer,” they added.

For the study, Hu and colleagues assessed the surgical outcomes of MIRP versus RRP in nearly 9,000 men with prostate cancer. Nearly 2,000 of the men had MIRP, the others had RRP.

The data they used came from US Surveillance, Epidemiology, and End Results Medicare linked data.

The results showed that over the study period, MIRP use went up by nearly five-fold, from 9.2 per cent in 2003 to 43.2 per cent in 2006-07.

When they analyzed the data, Hu and colleagues found that compared to those who had RRP, the men who had MIRP:

  • Spent less time in hospital (median hospital stay was 2.0 days for the MIRP patients versus 3.0 days for the RRP patients).
  • Were less likely to receive a blood transfusion (2.7 per cent for MIRP versus 20.8 per cent for RRP).
  • Had a lower risk of postoperative respiratory complications (4.3 versus 6.6 per cent respectively).
  • Had a lower risk of miscellaneous surgical complications (4.3 versus 5.6 per cent).

However, in respect of longer term outcomes, the researchers found that:

“Men undergoing MIRP vs RRP experienced more genitourinary complications [involving the genital and urinary organs or their functions; 4.7 per cent vs 2.1 per cent] and were more often diagnosed as having incontinence and erectile dysfunction.”

“The need for additional cancer therapies was similar by surgical approach,” they added.

The authors concluded that:

“Men undergoing MIRP vs RRP experienced shorter length of stay, fewer respiratory and miscellaneous surgical complications and strictures, and similar postoperative use of additional cancer therapies but experienced more genitourinary complications, incontinence, and erectile dysfunction.”

The researchers also found that compared to men who underwent RRP, the men who had MRIP were more likely to be living in areas of higher socioeconomic status (based on education and income). They suggested this could be a result of:

“A highly successful robotic-assisted MIRP marketing campaign disseminated via the Internet, radio, and print media channels likely to be frequented by men of higher socioeconomic status.”

They also suggested that men of higher socioeconomic status going for high-tech surgery, despite there not being enough data to show it was superior to the established “gold standard”, reflects:

“A society and health care system enamored with new technology that increased direct and indirect health care costs but had yet to uniformly realize marketed or potential benefits during early adoption.”

There has been a mixed reaction to the study.

Ryan Rhodes, marketing director for Intuitive Surgical, the company that makes the da Vinci robot used in robot-assisted MIRPs, told the Associated Press (AP) that there have been more than 800 previous studies on robot-assisted prostate surgery, and the “overwhelming majority of these show superior results”.

According to Reuters, Rhodes also stressed that the researchers in this study used data extracted from Medicare billing records, which do not distinguish between robot-assisted and other forms of MIRP.

A doctor who does similar research at the University of Chicago Medical Center, Dr Greg Zagaja, and who wasn’t involved in the study, also told AP that the Medicare billing codes don’t necessarily represent the surgical outcomes. He noticed there was no difference in the rate of procedures for treating sexual dysfunction and incontinence between the two groups.

Meanwhile the Los Angeles Times (LAT) has reported comments from a leading researcher and advocate of open radical prostatectomy, Dr Herbert Lepor, chairman of the department of urology at NYU Langone Medical Center.

Lepor, who was also not involved in the study, commented that in recent years MIRP has been marketed as being comparable to or better than open surgery. He said all the claims that are driving the robotic surgery are “not based on any credible evidence”.

“We have to ask, how is this technology impacting our healthcare delivery? It has increased costs, and what have we gained? It looks like we are going backward in the most important clinical outcomes,” said Lepor.

Lepor is investigating the impact of prostate cancer surgery on patients’ long term satisfaction, and has recently presented some findings at the annual meeting of the American Urological Association.

According to the LAT report, he explained that they found six months after surgery, patients were not concerned with whether they went home in two or three days or needed a transfusion:

“It’s continence, erections and disease recurrence. That is what is relevant,” said Lepor.

However, in a separate press briefing about the study, Hu said even if robotic surgery eventually proves to be better for all men, there is a learning curve for surgeons using the procedure, and he suggested more studies should be done to look at the rate of complications as surgeons get better at using the robot.

In the AP report, Zagaja said the best advice he had for men trying to make a decision about robot-assisted MIRP was to ask how many robot-assisted procedures a surgeon had done.

“Comparative Effectiveness of Minimally Invasive vs Open Radical Prostatectomy.”
Jim C. Hu; Xiangmei Gu; Stuart R. Lipsitz; Michael J. Barry; Anthony V. D’Amico; Aaron C. Weinberg; Nancy L. Keating.
JAMA. 2009;302(14):1557-1564.
Published online 14 October 2009.

Source: JAMA/Archives, Associated Press, Reuters.

Written by: Catharine Paddock, PhD