Suarez directed us to a Japanese study that found promising results from HIFU: It found a cancer cure rate of 91 percent for low-risk patients and reported that 80 percent of patients retained sexual function. But other studies "Nightline" reviewed found far less favorable results.
"All therapies have some degree of efficacy," Suarez said. "But efficacy is not always the entire answer. The collateral damage and other issues are equally important to patients."
Walsh said, "There is no good evidence at this point that HIFU can effectively cure prostate cancer without significant side effects."
The most common treatment for advanced prostate cancer is surgical removal. And in the hands of a skilled surgeon there is no question it works. Most men are cancer free after five years, but on average 50 percent of them will be left impotent. And that may be why men like Brightmire are prepared to take a leap of faith and pay the hefty price.
"The truth of the matter is it costs less than an operation in the United States, less than radiation therapy," Suarez said. "[It's] a fraction of what an American would be paying if he had to pay out of pocket."
His critics disagree. They worry that Suarez has a major business incentive to promote the procedure.
Suarez counters that he has sacrificed a large part of his practice by spending so much time away from it. "I could stay at home and probably have more financial incentive to operate," he said. "But the fact is … I do believe in this technology."
It is not just patients who are making the pilgrimage to Cancun and to Canada for this procedure, so are American urologists such as Hugh Solomon from Ann Arbor, Mich., and Gene Rosenberg from Hackensack University Medical Center in New Jersey.
Both men came to Cancun at their own expense to learn more about the procedure, even though FDA approval is still years away. Suarez said that "we've had several hundred urologists come for training."
"I'm here because there are many patients in my practice who don't fit into the usual treatment protocols that we have," Rosenberg said.
He added, "The United States, justly so, wants to see the evidence before they allow it to be used in the United States. I think that's a fair requirement. However, many of our patients' disease won't wait for that time to come."
Brightmire didn't want to wait, and he was willing to pay the steep price as well as the travel costs. Brightmire is no Palm Beach millionaire. He's a former Army helicopter pilot and a former National Park Ranger who dipped into his savings to pay for the treatment.
"I flew helicopters all my life and they needed maintenance and so I see the same is true for my body," he said the night before the operation. "And it costs a lot of money and time to keep a helicopter flying safely, so I do not mind putting the money into my body."
He added that "a lot of people worry about the expense, but I don't think you can put your money into anything better than yourself, your health."
An hour after the procedure was over, he walked out of the hospital holding his wife's hand. He said the day marked "a new beginning" with "no cancer."
That is certainly the hope. He's betting his life and $25,000 on it, and he will have to get tested regularly to know for sure.