The number of robotic general surgery procedures performed in the United States reached 140,000 in 2015—more than triple the number done in 2012, surgeons reported at the 2016 Annual Minimally Invasive Surgery Symposium (MISS). But it’s a boom going on amid a rigorous debate over the robot’s clinical and financial value.

Representatives of Intuitive Surgical said hernia repair and colorectal procedures are driving the uptake, particularly after results from a rectal surgery study were published this spring.

Use of robotics for rectal resection increased from 1% to 13%, and for colon resection use went from 0% to 4% between 2009 and 2014, according to the report at MISS.

The trend is expected to continue, Bradley R. Davis, MD, chief of colon and rectal surgery at Carolinas Medical Center, in Charlotte, N.C., said during a presentation at the meeting.

“I think robotic surgery will likely represent the biggest growth area for colorectal surgery in the next few decades,” he said.

The increase in robotics is in contrast to trends for laparoscopic surgery in colorectal surgery. Laparoscopy has stabilized in adoption across the United States over the last few years. Between 2009 and 2014, rates of laparoscopic utilization in colorectal surgery increased by 2% to 19% for rectal resection and by 4% to 43% for colon resection.

“Relative to laparoscopy, robotics is not plateauing. It’s continuing to go up, and that’s true of all the robotic procedures I looked at,” said Dr. Davis, who has trained on the robot but rarely uses it.

“Fundoplication, cholecystectomy, Roux-en-Y gastric bypass—we’re seeing the robotic curves go up and laparoscopic curve plateauing.”

But the rise in colorectal and general surgical procedures appears to be out of proportion with the strength of the literature.

Dr. Davis said the quality of the medical literature regarding the robot is “mediocre.”

He added, “Unfortunately, spin is very common in the literature relative to robotic surgery.”

So far, the most oft-cited benefits of robotic or robotic-assisted surgery are experienced by the surgeon rather than the patient: The robot is comfortable; articulation is better; tremors are reduced; vision is three-dimensional; and the approach does not require the ancillary team needed for laparoscopy.

However, these surgeon-centered advantages will become more important over the next decades as the general surgery workforce ages, said Dr. Davis. In 2010, 45% of American general surgeons were 55 years of age or older, according to data from the American Medical Association Physician Masterfile and the American Board of Medical Specialties.

“We’re going to see a lot of general surgeons who are going to work longer, and they’re going to appreciate the comfort afforded them by the robot,” Dr. Davis said.

Today, most graduating fellows in colorectal surgery are trained on the robot, as well as laparoscopic and laparoscopic-assisted approaches. This is expected to further fuel the practice of robotic colorectal surgery, he said. It may be that as surgeons become more experienced in the robot, patient outcomes will further improve.

It’s often argued that the robot opens the door to minimally invasive techniques for surgeons whose prior experience is predominantly open surgery, which unquestionably occurred in gynecologic surgery. Dr. Davis argued, however, that this is not the case in colorectal surgery, which has differed from other areas of surgery. Robotic or robotic-assisted colorectal surgery is performed almost exclusively by high-volume, expert minimally invasive surgeons, he said.

“These are not individuals who moved from doing open surgery to robotics. The robot is not able to compensate for marginal skill sets in colorectal surgery.”

It is difficult to make an economic argument for the robot. The platform costs between $1.5 and $2.3 million, plus upkeep and other associated costs. Laparoscopic surgery, in comparison, can be cost-effective compared with open surgery. A 2012 analysis found laparoscopic resection for colorectal cancer results in decreased costs and equivalent quality of life, making it the preferred approach in suitable patients (Dis Colon Rectum 2012;55:1017-1023). That said, many supporters of the robot argue that costs will decrease in the future as more robotic platforms become available.

Beyond economic concerns, many surgeons say they are worried about lack of evidence showing a benefit for the robot. The evidence varies depending on the area of general surgery, but the adoption of robotic surgery has undoubtedly outpaced the medical evidence. Two studies shed light on this phenomenon.

According to a 2015 study, more than 80% of studies comparing robotic colorectal surgery with other techniques overplayed the benefits of robotic surgery, known as “spin” (Dis Colon Rectum 2015;58:878-884). The most common form of spin was concluding equivalence between surgical techniques despite a finding of insignificant differences, noted in 76% of abstracts and 71% of conclusions. A claim of improved benefits, despite insignificance, was observed in 26% of abstracts and 45% of conclusions. In all, 34 of 38 studies in the analysis were observational in design and lacked power calculations to detect true differences, the researchers found.

“The suggestion that robotic colorectal surgery is safe, feasible and equivalent was pervasive. Although the intent of the authors of these previous studies was not likely to mislead the reader, the result may be just that in some circumstances,” they concluded.

They noted that spin also was a factor in reports of randomized controlled trials comparing laparoscopic and open techniques in lower gastrointestinal surgery, although less pervasive.

In a recent report in urology, in which the robot rapidly diffused into clinical practice, researchers found that teaching hospitals led the adoption of the robot, but faculty at teaching hospitals did not generate corresponding strong evidence on comparative effectiveness (Med Care Res Rev 2016 Mar 30. pii: 1077558716642690). The adoption was so rapid that, by 2010, 67% to 85% of radical prostatectomies in the United States were robotically assisted procedures. Two years before, there were only 24 published studies comparing robotic prostatectomy outcomes to those of conventional techniques, the authors found. Just 10 of the studies (42%) were more than minimally powered, and only six (25%) involved cross-institutional collaborations.

“In adopting the surgical robot, teaching hospitals fulfilled their mission to innovate but failed to generate corresponding scientific evidence,” the authors said.

However, there are arguments that evidence for the robot is building, particularly in rectal cancer. A meta-analysis of four randomized controlled trials comparing robotic-assisted with laparoscopic colorectal surgery concluded that robotic surgery is associated with decreased blood loss, a lower conversion rate to open surgery and quicker return of bowel function. However, the magnitude of the observed differences is small (World J Surg Oncol 2014;12:122).

The most important piece, however, is the much talked-about ROLARR trial results, released last spring. At the 2015 annual meeting of the American Society of Colon and Rectal Surgeons, Alessio Pigazzi, MD, PhD, associate clinical professor of surgery at the University of California, Irvine, presented results from the ROLARR study, a randomized study of 471 patients who underwent robotic or laparoscopic resection for rectal cancer. The short-term analysis showed no difference in intraoperative complications, mortality or circumferential margin positivity, which was low in both groups and 5.7% overall. Operating time was 261 minutes in the laparoscopic group and 298.5 minutes in the robotic group. The conversion rate, the primary end point of the study, was 12.2% in the laparoscopic group and 8.1% in the robotic group (odds ratio, 0.61; 95% CI, 0.31-1.21). The rate of conversion to open surgery that was used in this study was an indicator of surgical technical difficulty.

There were some populations of patients in whom conversion rates dropped with the robotic approach, including male patients (8.7% vs. 16%), obese patients (28.9% vs. 18.9%) and those undergoing low anterior resection (7.2% vs. 13.3%).

Dr. Pigazzi, who spoke at the MISS meeting, said, “We can say that, at the moment the robot has a role in TME [total mesorectal excision] for the more difficult cases, men with low tumor and obese patients, which intuitively makes a lot of sense.”

He noted that laparoscopic rectal surgery remains controversial, but “there are some benefits to robotic rectal resections compared with laparoscopy, especially with rectal cancer.”

Not all surgeons agree. Steven Wexner, MD, PhD, director of the Digestive Disease Center and chair of the Department of Colorectal Surgery at the Cleveland Clinic, in Weston, Fla., argues that the ROLARR trial demonstrated no statistically significant oncologic or clinical advantages, despite the study design as a superiority trial for conversion.

“There was no statistically significant benefit, but yet people keep doing it. My suspicion is that it’s a matter that people are afraid that if they don’t do it, somehow they’ll lose market share,” he said.

He called the rapid adoption of the robot in colorectal surgery “somewhat incongruous” compared with the state of the evidence. “When we went from laparotomy to laparoscopy, there were immediate differences seen: less pain, shorter hospital stay, quicker recovery, less resource utilization. Laparoscopy very quickly went from being more expensive to being much less expensive, in part, because of much lower complication rates and shorter hospital stays. None of these advantages have yet been seen when comparing robotic to laparoscopic colorectal surgery. Despite getting the same outcomes, the price to do it is significantly higher.”

He believes that the robot also could allow surgeons who are uncomfortable or unfamiliar with laparoscopic proctectomy to move to minimally invasive surgery, but with the end result that more proctectomies would be performed by lower-volume surgeons.

Dr. Davis said the robot’s place in colorectal surgery has shifted, and it’s now a legitimate treatment option in colorectal surgery. Until recently, he would have categorized the robot as an example of “supply-sensitive care”—when the supply of a specific resource, like a robot, was the major driver of utilization rates, out of proportion with medical evidence. But now, he believes that robotic surgery has shifted into “preference-sensitive care”: The robot is now an option supported by medical evidence and decisions about which operative approach should reflect patients’ values and preferences, Dr. Davis said.

“We’re now in preference-sensitive care where doctors have to talk to their patients about what their options are.

“What we need are more outcomes, more shared decision making with our patients in order to find what’s the best option because robotics is where I think you’re going to see the largest growth.”

In spring 2016, Intuitive reported another substantial increase in the number of robotic general surgical procedures performed. In their first quarterly statement for 2016, Intuitive reported a nearly 17% rise in da Vinci procedures worldwide over the last year—a growth driven primarily by an uptake in U.S. general surgical procedures and worldwide urologic procedures, they said.