Robotic-assisted minimally invasive surgery does not appear to offer any clinical benefits over conventional laparoscopic techniques in terms of outcomes and complication rates but is associated with significantly higher costs, two new studies of cancers indicate.
The first study is a retrospective analysis of more 23,000 patients treated with radical nephrectomy for a renal mass over a 12-year period.
Robotic-assisted surgery, which dramatically increased in use over the course of the study, did not improve postoperative complication rates. But it cost $2600 more than conventional surgery and increased the risk for a prolonged operation, report the authors, led by Benjamin I. Chung, MD, Department of Urology, Stanford University Medical Center in California.
The second study is randomized controlled trial of robotic-assisted vs laparoscopic rectal cancer surgery. There were no significant differences in conversion rates to open surgery or in complication rates and quality-of-life outcomes, report the investigators, led by David Jayne, MD, Department of Academic Surgery, St James's University Hospital, Leeds, United Kingdom.
The studies are published in the October 24/31 issue of JAMA.
In an accompanying editorial, Jason D. Wright, MD, Division of Gynecologic Oncology, Columbia University College of Physicians and Surgeons, New York City, says that the studies "highlight 2 important trends that have emerged for robotically assisted surgery."
The first is that the benefits of robotic-assisted procedures "have been more difficult to document." That's because there is often "no meaningful incremental benefit" in terms of complication rates or recovery compared with already established minimally invasive surgery.
The second is that the introduction of robotic-assisted technologies "appears to have substantially increased the number of patients who undergo a minimally invasive procedure" when, previously, minimally invasive surgery was slow to diffuse into practice.
Dr Wright suggests that money matters. "Without clear demonstration of improved outcomes associated with robotic-assisted procedures, the complicated issue of the cost will become increasingly important," he writes.
He notes that the techniques exemplify, from a policy perspective, "the difficulty of balancing surgical innovation with evidence-based medicine."
Speaking to Medscape Medical News, Dr Jayne said that the findings "throw the gauntlet down" to the manufacturers of robotic-assisted technologies.
He said that "the problem is the market has been dominated by one company who's had the monopoly on this, and so they've been able to charge what they want." As a result, the technology is not cost-effective.
"The onus is really on other companies to step up and bring in devices and systems that are cost-effective," he said.
Nevertheless, Dr Jayne emphasized that he believes that robotic-assisted surgery is "where we see the future going," despite not yet being cost-effective.
He said, "We have to be very careful about throwing the baby out with the bath water. You know, computers weren't the same as they are today 10 years ago."
More Details on Studies
In the first study, Dr Chung and colleagues retrospectively examined the Premier Healthcare database to gather information on patients who had undergone robotic-assisted or laparoscopic radical nephrectomy for a renal mass at 416 hospitals in the United States between 2003 and 2015.
They included 23,753 patients, who had a mean age of 61.4 years; 58.1% were men. Of those, 18,573 underwent laparoscopic radical nephrectomy and 5180 had a robotic-assisted procedure.
During the study period, the proportion of robotic-assisted radical nephrectomies increased from 39 (1.5%) of 2676 procedures in 2003 to 862 (27.0%) of 4193 procedures in 2015 (P for trend < .001).
The team performed weighted logistic regression analysis, adjusted for age, sex, race, Charlson comorbidity index, insurance status, teaching status, number of beds, hospital location, surgery year, and hospital clustering.
This revealed that the incidence of any postoperative complications, defined as Clavien grades 1 to 5, did not significantly differ between robotic-assisted and laparoscopic radical nephrectomies, at adjusted rates of 22.2% vs 23.4%, an absolute risk difference of –1.2 percentage points and a risk ratio of 0.95.
A similar picture was seen for major complications (defined as Clavien grades 3 to 5), at adjusted rates of 3.5% with robotic-assisted surgery and 3.8% with laparoscopic procedures, yielding an absolute risk difference of –0.3 percentage point and a risk ratio of 0.93.
However, the likelihood of the procedure lasting more than 4 hours was significantly greater for robotic-assisted than for laparoscopic radical nephrectomy, at adjusted rates of 46.3% vs 25.8%, an absolute risk difference of 20.5 percentage points and a risk ratio of 1.79.
The researchers also found that robotic-assisted surgery was associated with significantly higher average 90-day direct hospital costs than were laparoscopic procedures, at $19,530 vs $16,851 (P = .004).
This was driven by significant differences in mean supply costs between the two procedures, at $4876 for robotic-assisted procedures vs $3891 for laparoscopic surgery (P < .001), and operating room costs, at $7217 vs $5378 (P < .001).
The team writes: "The use of robotic assistance was not associated with increased risk of any or major complications but was associated with prolonged operating time and higher hospital costs compared with laparoscopic surgery."
For the second study, Dr Jayne and colleagues conducted the Robotic vs Laparoscopic Resection for Rectal Cancer (ROLARR) trial to examine the safety, efficacy, and short- and long-term outcomes of robotic-assisted and laparoscopic rectal cancer surgery.
They randomly assigned 471 patients with resectable rectal adenocarcinoma at 29 sites in 10 countries, treated by 40 surgeons, to robotic-assisted or laparoscopic resection, performed via high or low anterior resection or by abdominoperineal resection.
The mean age of the patients was 64.9 years, and 67.9% were men. The study was completed by 466 (98.9%) participants.
The rate of conversion to open laparotomy was 10.1% overall, 12.2% for laparoscopic surgery, and 8.1% for robotic-assisted procedures, yielding an unadjusted risk difference of 4.1 percentage points and a nonsignificant adjusted odds ratio of 0.61 (P = .16).
The overall rate of circumferential resection margin positivity was 5.7%. Again, there was no significant difference between the laparoscopic and robotic-assisted surgery groups, at 6.3% vs 5.1%, an unadjusted risk difference of 1.1 percentage points and an adjusted odds ratio of 0.78 (P = .56).
There were also no significant differences between the two procedures for rates of intraoperative complications, postoperative complications, plane of surgery, 30-day mortality, bladder dysfunction, and sexual dysfunction.
The researchers write: "These findings suggest that robotic-assisted laparoscopic surgery, when performed by surgeons with varying experience with robotic surgery, does not confer an advantage in rectal cancer resection."
Dr Jayne suggested, however, that a different study design may have been able to detect a significant difference in the primary outcome of conversion to open surgery between the two types of procedure.
He explained that when the study was designed around 6 years ago, the best available evidence suggested that the conversion rates should be approximately 20%. The study was consequently powered to detect differences between robotic-assisted and conventional surgery on the basis of that rate.
"Our surgeons are obviously an awful lot better than we anticipated and so the conversion rate, rather than being 20%, came in at about 10% overall, and as a result, the study is…underpowered," Dr Jayne said.
This means that despite a numeric difference between the two study groups, the trend is not significant. According to Dr Jayne, "We have to be very careful about the conclusions we draw. The only conclusion we can draw is that there's no difference."
Differences in conversion rates were also seen in subgroups of patients who are associated with more difficult procedures: men with a tight pelvis, obese patients, and those with low rectal cancers.
"Again, we saw differences in the conversion between the two arms but, again, we can't say that they are significant," Dr Jayne said.
He added: "What it's looking like, probably intuitively, is the robot isn't needed for every operation but there may be benefits in the more difficult patients. But we haven't proven that in the paper."
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