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Finasteride: Are the Risks Worth it?

Finasteride: Are the Risks Worth it?

Updated: 12/21/2015

Does finasteride prevent prostate cancer? According to Patrick C. Walsh, M.D., University Distinguished Service Professor of Urology at Johns Hopkins Medicine, it just prevents you from knowing that you have it. Even worse, taking finasteride may mask the signs of aggressive, yet curable prostate cancer until much later.

Many of Dr. Walsh’s patients have asked him about an article that appeared in The New York Times on Sunday, June 15, 2008. It claimed that finasteride somehow helps men by preventing them from knowing they have prostate cancer so they can avoid the potential side effects of treatment.

Finasteride hides higher-grade cancer

The trouble with finasteride dates back to 2003 when the original article was published in the New England Journal of Medicine. The authors of that article studied 18,000 men who randomly were assigned to receive either 5 mg of finasteride (then used mainly to treat benign enlargement of the prostate) or a placebo.

The men in the finasteride group had a 25 percent lower risk of being diagnosed with prostate cancer, but a 68 percent higher risk of being diagnosed with a high-grade disease defined by a Gleason score of 7 to 10. (This high-grade type of cancer is usually more difficult to cure.) Since then, the authors of the article have tried to erase these results and encourage urologists to prescribe finasteride for prostate cancer prevention. When these attempts failed, they started approaching patients and physicians directly.

No Decrease in Positive Biopsies

During the first seven years of the study, the patients had a biopsy if they had an abnormal finding on a digital rectal exam or if their PSA became elevated. But because this was a double-blind study, the patients taking finasteride did not know that their PSA levels were artificially low.

Therefore, fewer patients taking the drug who were told to have a biopsy followed that advice. Were there fewer cancers in these patients because finasteride actually prevents cancer or because fewer men got a biopsy in the first place? Did their low PSA levels fool them into thinking they couldn’t possibly have cancer? In this study, 15 percent fewer men on finasteride underwent a biopsy because they were lulled into a false sense of security by their low PSA level.

Thus, the major effect of this drug was to keep patients from knowing that they even needed a biopsy. Of the men in the study who actually had a biopsy, the frequency of positive biopsies for cancer was statistically the same in patients in both test groups.

Dr. Walsh is very concerned about the increase in high-grade disease and the possibility that this presents an unacceptable risk for a form of treatment that has little or no value.

Among finasteride’s critics is Stewart Justman, who wrote a book called Do No Harm: How a Magic Bullet for Prostate Cancer Became a Medical Quandary. In his review of the publication for the New England Journal of Medicine, Dr. Walsh noted that when patients on finasteride are diagnosed with prostate cancer, they are more likely to have dangerous, high-grade disease.

The real danger is that many patients will be lulled into a false sense of security. If you are told that you’re on a drug that will prevent cancer, and your PSA falls, you aren’t going to be on your guard.

Risky Business for Two Patients

Dr. Walsh has seen this risk in action in multiple patients. Two cases involved men who had been taking Propecia, a form of finasteride that’s used to restore hair loss, for 10 years. One man had a PSA of 3.8 ng/ml, and the other had a PSA of 4 ng/ml. Since finasteride lowers PSA levels, some calculations are needed to determine the true PSA number for each patient. These men actually had PSA levels between 9 ng/ml and 10 ng/ml. Both of them had high-grade prostate cancer classified as Gleason 8 disease that had spread outside the prostate. One of them had a positive surgical margin. If surgical margins (the edges of the removed tumor) are positive, they show cancer cells or indicate that the cancer is just a short distance from the edge of the specimen.

Avoid finasteride to save money and reduce risk of high-grade disease

Dr. Walsh has been greatly troubled by the pressure for patients and general physicians to use finasteride. His conclusions about this drug include:

  • It has no primary effect in reducing the number of men who will have a positive biopsy.
  • Patients will believe that it prevents cancer, will be pleased that their PSA levels fall and will not understand the potential danger of developing undiagnosed, high-grade disease.
  • Finasteride can be used as a treatment for an enlarged prostate, as long as patients who are being screened for prostate cancer understand the guidelines. If you don’t want to know if you have prostate cancer, you should just avoid PSA testing.

According to Dr. Walsh, if you want to prevent prostate cancer, finasteride is the last thing you should take. Save yourself the yearly cost of the medication and avoid the increased risk of high-grade disease. The only thing that finasteride can do is prevent you from knowing that you may have lethal cancer until it may be too late to cure.


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