Prostate Cancer Therapy May Affect Mental Function

And a second study suggests a tumor-preventing drug saves men's lives

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HealthDay Reporter

MONDAY, Feb. 28, 2005 (HealthDay News) -- Hormone therapy used to fight prostate cancer may adversely effect men's mental abilities, a small Finnish study suggests.

The study is one of two in the March 1 issue of Cancer that address the balance of benefits vs. risk of prostate cancer medications. The second study finds that widespread use of the drug finasteride (Proscar) to prevent prostate cancer can save lives overall, although some men given the drug may develop very aggressive cancers.

The Finnish study reported tests on 23 men treated for prostate cancer at Turku University Hospital. The men received two drugs, flutamide and leuprolid; each work by cutting production of testosterone and other male hormones known to promote prostate cancer growth.

Tests given six months after initiation of hormone-reducing therapy revealed significant declines in the patients' visual memory, and also in recognizing and remembering numbers. However, by the one-year mark these patients also developed a slight improvement in verbal fluency, the researchers add.

The findings have implications for patient care, in that patients may want to be forewarned of these potential side effects before embarking on hormonal therapy, the researchers conclude.

The Finnish study is just the latest to report these types of mental effects, said Susan F. Slovin, a medical oncologist at Memorial Sloan-Kettering Cancer Center in New York. She said that, like most of the other studies preceding it, its findings should be approached with caution due to the small number of patients in the trial.

"All of these studies have been very limited as to the number of patients involved," she said.

"In general, most of us would agree that it [hormonal therapy] is a very safe treatment," Slovin said. One problem in interpreting the results of this and other reports is that this type of treatment is often given to older patients, some of whom already are experiencing a decline in mental function, she noted.

The New York specialist worries that "a small paper such as this can prevent patients from going on medications that are good for them. The benefits far outweigh the risks," she said.

The second study analyzed data from the landmark Prostate Cancer Prevention Trial, involving more than 18,000 healthy men. Some received finasteride, while others got a placebo. The trial, scheduled to last seven years, was cut short early because researchers found a nearly 25 percent reduction in the incidence of prostate cancer in the men taking finasteride.

However, that good news was tempered by the fact that the overall incidence of aggressive cancers was doubled in the men who took finasteride compared to those did not. So while most participants benefited from the drug, a minority may actually have fared worse.

Because of that paradox, "there was controversy about whether or not it was worth giving finasteride to the general population," said Joseph M. Unger, the Prostate Cancer Prevention Trial statistician who performed the new analysis.

According to the trial results, providing finasteride to all men over 55 years of age would save 316,760 person-years of life over 10 years, Unger said. Lives lost because of an estimated 6.9 percent increase in high-grade cancers linked to finasteride use would reduce survival to 262,567 additional person-years, he said, but that would still represent a significant net benefit to patients overall.

"This analysis shows that the benefits far outweigh the risks," said Unger, who works at the Fred Hutchinson Cancer Research Center, in Seattle.

According to Slovin, the finasteride trial has produced "mixed emotions."

"People are concerned about anything that may influence outcome of the disease," she said.

Family doctors in general are not prescribing finasteride for healthy men, Slovin noted. Instead, "a family doctor makes a referral to a urologist for someone who is having symptoms."

The benefit-versus-risk equation means that "patients have to discuss this with physicians, and physicians have to be very upfront about it," Slovin said.

More information

Overviews of prostate cancer, its prevention and treatment, are offered by Memorial Sloan-Kettering Cancer Center and the National Cancer Institute.

SOURCES: Susan F. Slovin, Ph.D, medical oncologist, Memorial Sloan-Kettering Cancer Center, New York City; Joseph M. Unger, M.S., statistician, Southwest Oncology Group Statistical Center, Fred Hutchinson Cancer Research Center, Seattle; Feb. 28, 2005, Cancer

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