Researchers suggest men speak with their physicians about their prostate specific antigen (PSA)levels, and about potential use of finasteride, so that they will make a decision that is right for them. (CBC)

A drug that helps prevent prostate cancer but was once seen as risky is now being painted in a new light.

Finasteride, which belongs to a class of drugs called 5-alpha reductase inhibitors, decreases the body's production of androgen testosterone, a male hormone that causes the prostate to enlarge. In a 2003 study of 18,822 men, it was found to reduce a man's chance of getting prostate cancer by 25 per cent.

However, initially, there were concerns that when men taking the drug developed prostate cancer, the tumours were more advanced than in men with the disease who were not on the drug.

That thinking has changed following a comprehesive re-evaluation of the study. Two studies released last week that will be published in the June issue of Cancer Prevention Research shed new light on finasteride.

"We found that the drug actually worked to reduce the incidence of prostate cancer and more importantly, did not increase the incidence of high-grade cancer," Dr. Steven Kaplan, associate professor of urology at Weill Cornell Medical College, told CBC News.

In fact, said Kaplan, the review shows that the drug reduces a man's risk of developing prostate cancer by 30 per cent. And researchers now believe the drug doesn't cause more aggressive tumours — it just makes them easier to find because it shrinks the prostate.

"It's easier to find a cherry pit in a cherry than it is in a watermelon," said Kaplan. "So from the perspective of finding a tumour, it's much easier to find in a smaller prostate."

The drug is now thought to reduce aggressive tumours by 27 per cent.

Hans Hoeflein, a 76-year-old resident of Palmer Township in Pennsylvania, was given finasteride for seven years in the original trial and is still free of cancer.

"So if the doctor was to come to me as a result of some diagnosis he made and wanted to prescribe finasteride — I would certainly take it," he said.

Men urged to consult with doctors

Montreal urologist Dr. Fred Saad has already been prescribing finasteride to his high-risk patients, and expects to see it used even in older men who have no risk factors.

"If we're worried about having prostate cancer, well there is something that we can do to try to be proactive to try to reduce that risk," he said.

Researchers suggest men speak with their physicians about their prostate specific antigen (PSA) levels, and potential use of finasteride, so that they will make a decision that is right for them.

PSA is an enzyme produced in the ducts of the prostate and absorbed into the bloodstream. A score of four and under is considered normal, while a score over four could indicate the presence of cancer.

Finasteride is cheaper in the U.S. where it's available as a generic. The patent expires in Canada in a few years, meaning generics may be produced.

Finasteride's side-effects, which are usually reversible once the drug is stopped, include:

• Impotence.
• Decreased libido and ejaculate.
• Breast enlargement or lumps.