Uncertainty Remains About Drugs to Reduce Risk of Prostate Cancer

Howard LeWine, M.D.

Q: My doctor told me that my prostate gland is enlarged. I don't have any symptoms and my PSA test has always been normal. I read that a drug to treat an enlarged prostate may also protect against prostate cancer. Is this something I should consider?

A: Two related drugs used to treat men with symptoms of an enlarged prostate may decrease the risk of prostate cancer. Or it may be that they just delay the age at which prostate cancer starts. But there's no proof that they decrease the risk of death caused by prostate cancer -- the most important statistic.

The two drugs, finasteride (Proscar) and dutasteride (Avodart) are approved for benign (noncancerous) prostate enlargement. They work by blocking the production of a male hormone called dihydrotestosterone (DHT) that stimulates prostate growth. By shrinking an enlarged prostate, finasteride and dutasteride can slow progression or even reverse bothersome urinary symptoms, including:

-- A frequent urge to urinate

-- Trouble starting and stopping urination

-- A sudden inability to urinate

-- A slow stream

-- Getting up at night frequently to urinate

In addition, finasteride or dutasteride may delay or eliminate the need for prostate surgery to treat an enlarged prostate.

The results of the two large studies on finasteride and dutasteride did show that the men who took the active drug had fewer prostate cancer diagnoses compared to the men who took the placebo. However, the men who took the drugs had more side effects, including a higher rate of sexual dysfunction. Another concern: Men taking a DHT blocker who do develop prostate cancer appear to have a higher risk of that cancer being the more aggressive type. Also with dutasteride, there was an increased risk of heart failure.

Since you have no symptoms and an enlarged prostate does not increase the risk of developing prostate cancer, I would not recommend taking either drug.

There are other ways to help decrease your prostate cancer risk:

-- Maintain a healthy body weight.

-- Exercise regularly.

-- Eat a healthy diet. Although not proven, men who eat the following foods appear to have a lower risk of prostate cancer:

Tomatoes, especially cooked tomatoes

Fish, especially fatty fish

Vitamin D fortified foods and perhaps a daily vitamin D supplement

Foods rich in carotenoids (in addition to tomatoes) - these give fruits and vegetables their deep, rich colors

Green, leafy vegetables

Howard LeWine, M.D., is a practicing internist at Brigham and Women's Hospital, Boston, and Chief Medical Editor of Internet Publishing at Harvard Health Publications, Harvard Medical School.)

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