Researchers at the University of Texas Southwestern Medical Center say that men should weigh the potential benefits as well as side effects of a drug called finasteride before relying on it as a preventative medicine for prostate cancer.
The researchers say that they have analysed data gathered by the National Cancer Institute's Prostate Cancer Prevention Trial (PCPT), which began in October 1993 to test whether finasteride could prevent prostate cancer in men 55 years of age and older.
When the trial stopped early in June 2003, an analysis showed that finasteride could reduce the risk of developing prostate cancer by 25 per cent.
However, the latest analysis of the PCPT data indicates that cost effectiveness and quality of life issues associated with taking the drug are not clear-cut.
The PCPT data show that in addition to preventing prostate cancer, finasteride also reduces urinary tract symptoms associated with benign prostatic hyperplasia. It also decreased sexual desire and caused impotence in five per cent of the trial participants.
Some PCPT participants who did develop prostate cancer also had high-grade tumours, although there is ongoing debate whether this result might have been due to sampling bias.
"Finasteride is currently the only drug that has been shown to prevent prostate cancer in a large randomized trial but is used for this purpose in very few men," said Dr. Yair Lotan, assistant professor of urology and the Cancer study's senior author.
"A large number of patients are currently taking over-the-counter supplements to prevent prostate cancer, even though there is no scientific evidence to support these products' claims. It's important for patients to be aware of this scientific trial and to ask their doctors if finasteride could benefit them," Dr. Lotan added.
The author suggests that physicians and patients consider these of using finasteride, and work together closely to weigh how the medicine may affect quality of life on a case-by-case basis.
"With the exception of skin cancer, prostate cancer is the most common cancer in American men. Men who are at low risk for prostate cancer might view taking finasteride as not very cost effective when considering its impact on their quality of life. On the other hand, patients at high risk might see it as cost effective because it lessens their chances of developing prostate cancer," Dr. Lotan said.
"Because there is some complexity to the PCPT I think doctors hesitate to discuss its results. While I'm not advocating for the drug, I think physicians should mention finasteride, especially when their patients are asking questions about ways to prevent prostate cancer. Patients should understand and be aware of the proven science that's out there," the author added.