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The risk is small and other studies contradict this study, but researchers say it’s a possible connection worth studying. Getty Images

Almost every medical treatment carries the risk of side effects.

But as people age and the risk of developing different health conditions rises, they and their doctors increasingly have to make tough decisions about trade-offs.

Surgery for, say, a hip replacement may carry an increased risk of a potentially dangerous blood clot. Chemotherapy may increase the chances of infection or anemia.

New research presented earlier this month now suggests there might be another tough decision to add to the list.

Researchers say they’ve found that undergoing a type of treatment for prostate cancer called hormone therapy may be linked to an increased risk of developing dementia.

But cancer experts warn that the likely small risk shouldn’t outweigh the potential life-saving benefits of the treatment.

The research is preliminary and it only found an association — meaning it isn’t clear whether the treatment actually causes the memory-loss condition.

Simply being older could be a factor since prostate cancer starts on average around age 65, which is also the age after which dementia symptoms become more common.

But the research does underline the possible difficult choices some older people increasingly face as they enter their mid-60s, as well as a somewhat contentious medical debate.

In some situations, doctors will recommend hormone therapy for people with prostate cancer.

Hormones like testosterone can fuel the growth and spread of prostate cancer. So hormone therapy, also called androgen deprivation therapy (ADT), slows the body’s production of testosterone and other “male hormones.”

That, in turn, can slow the cancer’s spread and sometimes shrink the tumors it has caused.

The new research gathered data from more than 100,000 mostly white men. Those who received the hormone therapy were 22 percent more likely to develop dementia than men who hadn’t had that treatment.

They were 29 percent more likely to develop Alzheimer’s, the most common cause of dementia.

Those chances also increased if they were on hormone therapy for seven months or longer, the researchers found.

The research was presented earlier this month at the American Urological Association’s annual meeting in Chicago. It hasn’t been published in a peer-reviewed journal yet.

Experts noted that previous studies have sometimes found an association between cognitive decline and hormone therapy while other studies have not found a link.

“You can find abstracts on both sides of the ledger,” Dr. Mack Roach, an oncologist who specializes in prostate cancer at the University of California San Francisco, told Healthline.

A study published last year, for instance, found no association between dementia and hormone therapy for prostate cancer.

Another study last year found the therapy wasn’t associated with self-reported changes in cognitive ability.

But other research has found an association, including a 2016 study that said the therapy may be tied to a slightly increased frequency of dementia.

“I think that these sort of studies are dangerous,” Roach said. “I think the study itself is more dangerous than the [hormone therapy].”

That’s because Roach thinks reading about findings like this could dissuade people from getting treatment that has a high likelihood of saving or extending their lives.

“In all the studies, if the risk is there, it’s very small — and a fraction of the possible benefits of hormone therapy,” Roach said.

Roach said he wouldn’t want to give hormone therapy to someone who doesn’t need it, but if they do need it, studies like this wouldn’t dissuade him.

Dr. Stuart Holden, a urology oncologist at the University of California Los Angeles and medical director of the Prostate Cancer Foundation, said this information about recent studies does belong in the conversation when recommending hormone therapy to a patient.

“I think it should be mentioned,” Holden told Healthine. “It should be in the conversation, but it has to be placed in the proper context.”

That context, for him, would be that the hormone therapy comes with “a risk of cognitive impairment and possibly a small increased risk of dementia.”

The new study doesn’t “provide strong enough evidence, on its own, to change medical practice,” Heather Snyder, senior director of medical and scientific operations at the Alzheimer’s Association, told Healthline.

Her organization “strongly believes that all discussions about the potential benefits and risks of any treatment — including hormone therapy — should be had with a doctor. The decision should be made based on the patient’s unique health needs and circumstances.”

Age is the strongest risk factor for Alzheimer’s, Snyder said, although she noted that research is finding other factors “increase susceptibility or trigger the onset of dementia symptoms.”

The Prostate Cancer Foundation, which published a new guide for people with prostate cancer last week, helped fund the new research.

That was in part because there “always have been observations” of cognitive decline in some patients who get hormone therapy, said Holden, who has worked with the organization since its founding.

“It’s been a relatively minor occurrence, but one that is worth studying,” he said.

Holden said he’s always told patients that there may be some changes in their personality or mental state. That’s perhaps not surprising for a treatment that tries to remove a man’s “male” hormones.

Most men gain 15 to 20 pounds and lose muscle mass, he said, and it’s understandable the treatment could affect their brains as well.

Holden called the new research “a bit of a wake-up call” about a possible correlation to dementia. But he added that it’s not a study “that should create wholesale panic.”

“I can’t imagine any patient refusing to go on the medication due to the risk of cognitive impairment,” he said. “The more likely reason is that it can cause fairly significant sexual side effects, and that’s of much greater interest to most patients — and pretty much 100 percent [of patients who have those side effects].”

New research concludes that hormone therapy used to treat prostate cancer might create a slight increase in the risk of dementia.

However, other studies have found no connection and some experts believe the new study could lead some patients avoiding a life-saving treatment for the wrong reason.

Others believe it underlines a correlation that’s worth investigating further and mentioning, with some caveats, to patients.