One in five men who undergoes prostate surgery to treat cancer later regrets the decision, a new study shows. And surprisingly, regret is highest among men who opt for robotic prostatectomy, a minimally invasive surgery that is growing in popularity as a treatment.

The research, published in the medical journal European Urology, is the latest to suggest that technological advances in prostate surgery haven’t necessarily translated to better results for the men on which it is performed. It also adds to growing concerns that men are being misled about the real risks and benefits of robotic surgical procedures used to treat prostate cancer.

Of the 219,000 men in the United States who learn they have prostate cancer each year, nearly half undergo surgical removal of the gland, according to the National Cancer Institute.

Duke University researchers surveyed 400 men with early prostate cancer who had undergone either a traditional “open” surgical procedure or newer robotic surgery to remove the prostate. Overall, the vast majority of men were satisfied. However, 19 percent regretted their treatment choice. Notably, men who had undergone robotic surgery were four times more likely to regret their choice than men who had undergone the open procedure.

Researchers say the higher level of regret among robotic patients suggests that they had higher expectations for their recovery, possibly because the robotic procedure is widely touted as a more innovative surgery than traditional prostatectomy. Even among men who had the same scores on erectile function and other measures of post-surgery recovery, the robotic patients still reported a higher level of dissatisfaction and regret than other men.

Part of the problem may be that doctors who perform robotic prostatectomies commonly cite potency rates as high as 95 percent and above among their patients, giving patients an unrealistic view of life after surgery.

But the data are highly misleading. Researchers often define potency as simply being able to achieve an erection that is “adequate” for intercourse — but for many men, that definition doesn’t capture their ongoing struggle to return to a normal sex life. Earlier this year, researchers from George Washington University and New York University used a more realistic definition of potency, showing that after surgery, fewer than half of the men studied felt their sex lives had returned to normal within a year.

Another important finding of the new research showed that men were less likely to regret their choice shortly after surgery. The men who were long past surgery experienced more regret. That finding likely speaks to the fact that as time passes after surgery, men gain a more realistic view of lingering health and quality-of-life issues like erection problems and other changes in their sex lives.

The Duke researchers said that the study shows urologists need to communicate more carefully the risks and benefits of the treatment prior to surgery so that men have more realistic expectations of what to expect.