(CNN) A federal judge blasted UnitedHealthcare last month for its "immoral and barbaric" denials of treatment for cancer patients. He made the comments in recusing himself from hearing a class-action lawsuit because of his own cancer battle -- and in so doing thrust himself into a heated debate in the oncology world.

At issue is a treatment known as proton beam therapy, an expensive alternative to standard radiation that proponents say is a more precise form of treatment with fewer side effects. Opponents have questioned whether proton therapy is worth the high cost to fight some forms of cancer, and insurance companies have often denied coverage for the treatment, calling it "experimental."

The case that came before US District Judge Robert N. Scola was brought by a prostate cancer survivor who alleged that UnitedHealthcare wrongfully denied him and thousands of others coverage of proton beam therapy.

In his recusal, Scola cited his own battle with prostate cancer and how he consulted "with top medical experts around the country" about treatment options. Scola said that he ultimately opted for surgery but that "all the experts opined that if I opted for radiation treatment, proton radiation was by far the wiser course of action."

The judge also cited a friend who was diagnosed with cancer in 2015 and got hit with a $150,000 bill after UnitedHealthcare refused to pay for his proton beam radiation from MD Anderson Cancer Center. "Only upon threat of litigation did UnitedHealthcare agree to reimburse him," Scola wrote.

"It is undisputed among legitimate medical experts that proton radiation therapy is not experimental and causes much less collateral damage than traditional radiation," wrote Scola, a US District Court judge for the Southern District of Florida. "To deny a patient this treatment, if it is available, is immoral and barbaric."

UnitedHealthcare declined to comment about the remarks. Instead, the insurer noted that it updated its policies in January to allow more coverage of proton beam therapy for various cancers. In a major shift on prostate cancer specifically, the company said proton beam radiation and traditional radiation "are proven and considered clinically equivalent for treating prostate cancer."

"UnitedHealthcare works every day to ensure our members have access to proven, clinically effective care," spokesman Matthew Wiggin said. "We cover cancer therapies that have been clinically proven to be safe and effective, including, for some cancers, proton beam therapy. Our medical policies and coverage decisions evolve based on the most current published clinical and scientific evidence and we continually review and update these polices and coverage decisions."

The judge's comments were widely shared among patients and doctors who have felt stiffed by the nation's largest insurance company. But whether he intended it or not, they stirred controversy beyond social media.

The American Society for Radiation Oncology, or ASTRO, the largest organization of doctors who use radiation to treat cancer, acknowledged that the issue is one that stokes passion. Proton beam therapy can cost 60% more than standard radiation, even well over $100,000.

"The reason protons are controversial is for two reasons: because of the costs and the access," said Dr. William Hartsell, ASTRO's vice chairman for health policy. "I think if protons were more available and less expensive, there are a lot more patients who would get treated with protons."

Proton therapy targets difficult-to-treat tumors and allows for a higher dose of radiation to hit the targeted area, minimizing damage to other tissue, including vital organs. Standard radiation radiates the areas around a tumor rather than a pinpointed location. "We keep improving technology to do that better and better," Hartsell said. "So proton beam therapy is the next step."

ASTRO updated its guidance for insurers in the summer of 2017 with a host of cancers that the organization now believes could be treated with proton beam therapy and should be covered by insurance. The guidance replaced research published in 2012 that had found evidence was lacking for proton therapy in certain cancers, including lung cancer and head-and-neck cancer.

There are 31 proton beam centers in the nation and four more under construction, with the sites costing $100 million to $250 million depending on the size of the facilities, according to ASTRO. Hartsell said the 2012 research was based on information from 2009, when only five proton centers existed.

"There's been a huge change in the number of studies and amount of information since then," Hartsell said. "But I don't think everybody's kept up on that."

That includes insurance companies. Hartsell said a recent study showed that about two-thirds of cancer patients were initially denied proton treatment by their insurers: "If you have a patient, say with esophageal cancer, they can't wait four months for a decision on treatment."

"One of the problems we have right now with these [insurance] policies is, they are a one-size-fits-all policy," he said. "They're kind of removing the medical judgment of the people who are in the best position to make that decision."

He applauded UnitedHealthcare's recent decision to cover proton beam for prostate cancer when appropriate.

Two studies are ongoing to determine its effectiveness for prostate cancer, he said. In its 2017 guidance , ASTRO said proton beam's use in prostate cancer is still "evolving as the comparative efficacy evidence is still being developed."

And therein lies the rub among some doctors about the judge's comments: Treatment for localized prostate cancer remains a research question.

"The judge is wrong. He does not know the facts, and he has fallen for some of the advertising," said Dr. Otis Brawley, a professor of oncology at Johns Hopkins University's School of Medicine and the former chief medical officer at the American Cancer Society.

Brawley, who still sees prostate cancer patients, said the physics "of proton beam radiation therapy would suggest that it might have less side effects compared to conventional external beam radiation (IMRT) in the treatment of a number of diseases, including in the treatment of localized prostate cancer."

"This said, there is currently no evidence that proton beam radiation therapy offers any advantages over IMRT in the treatment of prostate cancer," he said.

The federal judge made his comments in response to a class-action lawsuit brought by Richard Cole, a cancer survivor and prominent Miami attorney. Cole was 70 when he was diagnosed with advanced prostate cancer in April 2018. "The first concern you have is: Am I going to die?" Cole said.

He said he consulted with his team of doctors at the Miami Cancer Institute and with others at the Memorial Sloan Kettering Cancer Center in New York. The consensus, he said, was that he needed proton beam therapy.

But he said he soon learned his treatment was being delayed because UnitedHealthcare refused to cover it. He paid the $85,000 out-of-pocket to undergo treatment as soon as possible while his attorneys appealed his denial.

"When delays occur because of bureaucracy," Cole said, "it gets you angry and upset."

His final appeal was denied in February, he said, even though UnitedHealthcare updated its policy a month before to allow coverage for prostate cancer. That policy change, he said, was the "proof in the pudding" that the lawsuit will hold up in court.

"How can you now change your position with no new studies and look at a jury or a judge with a straight face and say 'this man's cancer and many other people's cancer shouldn't be treated exactly that way'?" he asked.

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His suit also alleged that a subsidiary of the insurance giant has invested heavily in a proton center in New York.

If his case prevails, Cole said, he will donate any monetary award to the Miami Cancer Institute. "I certainly know that not many people can write a check for $85,000, and they shouldn't be foreclosed from getting the right treatment just because they don't have the available funds," said Cole, who has defended insurance companies -- just not health ones -- in his line of work as an attorney.

His most recent lab results showed that he is clinically cancer-free. He attributes his good health to his team of doctors and to proton beam therapy. He now wants more Americans to have access to the treatment.

His next major hurdle may be finding a judge who will preside over the case. Two other judges have also recused themselves due to their friendships with the well-known attorney.