TUESDAY, May 12, 2015 (HealthDay News) -- Men undergoing hormone therapy to treat prostate cancer may experience impaired mental function within the first six months that persists for at least a year, a new study suggests.
Moreover, the risk of memory, learning and concentration problems associated with hormone therapy was greatest for men with a particular gene mutation, researchers from the University of South Florida in Tampa found.
Hormone therapy is used to lower the level of testosterone, thus preventing growth of prostate cancer cells.
"There is something about the treatment that seems to be associated with worse mental function," said lead researcher Brian Gonzalez, a postdoctoral fellow at the Moffitt Cancer Center in Tampa.
But the association seen in the study does not prove a cause-and-effect relationship.
For the study, Gonzalez's team evaluated 58 prostate cancer patients before they began hormone therapy and six months and 12 months later. The investigators compared them with 84 men who had their prostate gland surgically removed and 88 men without prostate cancer.
Fuzzy mental functioning was worse for men receiving hormone-depletion therapy. But men with the gene mutation rs1047776 were 14 times more likely to have mental problems related to hormone therapy than men without this mutation, Gonzalez said.
"Men who are considering hormone therapy for prostate cancer should be aware of the possible mental side effects," Gonzalez said.
Gonzalez suspects altering testosterone levels might cause thinking impairments. But men on hormone therapy also experience fatigue and depression, which might affect their mental abilities, too, he said.
The report was published online May 11 in the Journal of Clinical Oncology.
Other experts aren't so sure about the extent of impairment -- or whether hormone therapy is even warranted for prostate cancer patients.
"This is a small study . . . that needs to be verified," said Dr. Anthony D'Amico, chief of radiation oncology at Brigham and Women's Hospital in Boston, who had no role in the study.
What is needed, he said, is a randomized study that compares similar men receiving hormone therapy with those not receiving this treatment. In addition, the duration of hormone therapy needs to remain constant, he said.
D'Amico does believe, however, that a biological reason exists for thinking and memory problems among men on hormone therapy.
He pointed to an earlier study that found long-term hormone therapy affected men's mathematical ability. "There is a basis for it. I don't discount it. I believe that these problems are probably true, but not to the extent reported in the current study," D'Amico said.
Current practice is to give hormone therapy for only a short time, he said. "I am not positive that short-course hormone therapy has any impact on mental function. I am fairly convinced that long-term therapy does," D'Amico said.
Also, whether mental function returns to normal after therapy ends isn't known, he said. "There are lot of questions that need to be raised," D'Amico added.
Dr. David Samadi, chairman of urology and chief of robotic surgery at Lenox Hill Hospital in New York City, doesn't think men with prostate cancer should have hormone therapy.
"Hormone therapy is absolutely not necessary," he said. "Not only do you have to worry about the side effects of fatigue, male menopause and depression but also heart problems," Samadi said.
"And what's not good for the heart is also not good for the brain," he said. "These mental issues are another reason to walk away from hormone therapy."
Samadi believes that with state-of-the-art surgery, men can have their prostate gland removed and not suffer from incontinence or sexual side effects.
For more on prostate cancer, visit the American Cancer Society.