Men treated with testosterone-lowering drugs for prostate cancer are at increased risk of dementia than patients who are not given testosterone therapy, reports a recent study.

Patients are treated with Androgen Deprivation Therapy (ADT) when their prostate cancer has started spreading to other parts of the body. Since testosterone is found to promote prostate cancer growth, ADT is used to decrease the levels of testosterone and other androgens in such patients. The therapy is being followed since the 1940s, and currently about half a million men in the United States are reportedly under ADT for prostate cancer.

Researchers from University of Pennsylvania Perelman School of Medicine (UP) and Stanford University School of Medicine (SU) studied the medical records of about 10,000 prostate cancer patients from Stanford Medicine's clinical research database. Of which, 1,829 patients were found to have received ADT.

Upon analysis, it was found that 7.9 percent of patients who received ADT developed dementia within the next five years while only 3.5 percent of prostate cancer patients who weren't put under ADT developed dementia. Though the risk is observed to be double, the overall percentage still appears small.

Dr. Nigam Shah, the senior author of the study from SU, said that there is an association between dementia and ADT and therefore patients with history of dementia might have to be given alternative therapy. He also noted that the study focused on cognitive decline and dementia as a whole instead of analyzing dementia and Alzheimer's disease risks individually.

Meanwhile, the study noted that prostate cancer patients survived for 10 years irrespective of the kind of treatment they received, which include radiation therapy, surgery and active monitoring. Regardless of the treatment given initially, 99 percent of patients were found to have survived. It is clear from the study findings that active monitoring that causes fewer side effects is as effective as other therapies.

Shah and Kevin Nead, the study's lead author from UP, also clarified that the study results and findings don't recommend men under ADT to discontinue or make any changes to the current therapy without consulting their physicians.

"We are working to make such studies as simple as a Google search. If we had infinite funding, we'd do a trial for everything. But we don't have that. These cheap, few-week studies can guide us where to point our clinical trial dollars," noted Shah about their retrospective approach of the study, reported in SU press release.

The study was published online in JAMA Oncology on Oct. 13.

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