Sixteen years ago, U.S. regulators approved a robotic surgery system named after a Renaissance genius: da Vinci. Hospitals, in a technological arms race to offer the most cutting-edge medical care, began to buy up the da Vinci Surgical System — and to advertise it on websites and billboards. Today, machines made by Intuitive Surgical, which still offers the only robotic-assisted surgical system in the United States, can cost up to $2 million. The vast majority of prostate cancer surgeries in the United States are done with its robotic assistance. The system magnifies the surgical site on a large screen and allows surgeons to control robotic arms from a console, with hand grips and foot pedals.

So it seems a little late for this: On Tuesday, the Lancet journal published the results of a randomized, controlled trial that compared robot-assisted prostate surgeries to traditional versions of the procedure. The Australian physicians who conducted the study concluded that the outcomes were similar and there was no reason to recommend the futuristic version over the old-fashioned one. The study found that — at 12 weeks follow-up — there was no significant difference in patients’ sexual function or urinary control. The group that had robotic surgeries had less pain at a day and a week after surgery, but both groups returned to work equally as fast.

The Australian team will continue to track the 250 men in their study to see if differences emerge at one and two years following surgery.

"In the interim, we encourage patients to choose an experienced surgeon they trust and with whom they have rapport, rather than a specific surgical approach,” the research team wrote.

The data isn't exactly a strike against robot-assisted surgeries for prostate cancer; there were benefits. Patients who underwent robot-assisted surgeries had less hospital-related anxiety and depression at 12 weeks and they lost less blood. Fewer patients had post-operative complications in the robotic-assisted group, but the difference was not statistically significant. And the surgeries were done by two different surgeons: a veteran surgeon did the traditional, open surgeries, while the robot-assisted laparoscopic surgeries were done by a surgeon with less experience.

The new study shows that “robotic-assisted surgeons are able to deliver treatment and care that can make surgery easier on patients,” Justin Higgs, a spokesman for Intuitive Surgical said in a statement. “Each of these benefits has cost-savings associated with it and when factored into the overall cost to treat, has a potential to demonstrate the cost of care value of minimally invasive surgery."

He pointed to a study, funded by the company, that found similar costs across different surgical methods.

But the findings burst the idea that robot-assisted surgeries are a profound leap ahead. It serves as a reminder that in medicine, progress and novelty aren't always the same thing. Robot-assisted surgeries were initially marketed directly to consumers and were a point of pride for hospitals — even as the medical evidence to support their superiority was thin.

That arc shines a spotlight on how medical innovation often works. Costly and exciting new drugs, procedures or tools can become widespread before there's evidence they really are better, especially as hospitals compete. Take proton beam therapy, which sounds like a much better way to irradiate tumors because it reduces radiation exposure in surrounding tissue. In prostate cancer, where the technology is frequently used, the jury is still out on whether it leads to better results for patients over cheaper radiation therapy.

Some studies have found that robot-assisted surgeries are more costly to the health system. Even factoring in a slightly shorter stay in the hospital, the benefits did not lead to a reduction in spending, according to a 2014 study in the Journal of Clinical Oncology, which found that the robot surgeries cost $1,400 more.

Vincent Laudone, a urologic surgeon at Memorial Sloan Kettering Cancer Center, who did open prostate surgeries for the first two decades of his career, but has switched to robot-assisted surgeries for the last 13 years, said that what appeals to him is the magnification offered by the surgery — instead of wearing magnifying glasses, the area he operates in can be blown up to reveal greater detail on a giant screen. He said he also saw reductions in the amount of blood lost and shorter hospital stays for his patients.

"Those of us that have converted from one to the other believe our outcomes, individually, are better and that's why we’ve chosen to stick to robotics," Laudone said. "I came into this as a skeptic 13 years ago."

He added, however, that the virtual monopoly enjoyed by the robotic systems maker has dampened innovation. Although the Intuitive Surgical robotic system is on its fourth iteration, "there are no real strong competitors in the field at this time. ... Even though we are 16 years into this, we haven’t see the real, technological breakthroughs that will come from having other players in the field," Laudone said.

Martin Makary, a pancreatic surgeon at Johns Hopkins University School of Medicine, who has studied robot surgeries said that his own conversations with prostate surgeons have led him to believe there are benefits, both because of the magnification and because surgeons aren't stooping over and exposing themselves to occupational hazards.

What's clear, Makary said, is that the initial marketing claims that fueled the uptake of the technology often overstated the case.

"I think, for all of the claims of superiority, it’s interesting that a study — after massive widespread adoption of robotic surgery — shows there’s no difference. That, if in fact there really is a superiority of robotic surgery, it’s probably a minimal advantage. It may be better, but it’s probably small margin of an advancement from the previous standard of care," Makary said. "That’s not to say we shouldn’t do it. But we’ve been sold a very expensive technology."

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