Finasteride, To Take, or Not to Take

A new study supports previous findings that finasteride prevents prostate cancer. However, like much research in prostate cancer, the study leaves us with as many questions as answers.

Prostate cancer is the most common non-skin cancer and the second leading cause of cancer mortality in American men. Although progress has been made in fighting this disease, there is still no universally agreed-upon strategy for its diagnosis and management. Finasteride has been shown to reduce the incidence of prostate cancer by up to 25%. Yet the use of this drug remains low, largely due to reluctance by men over the drug’s reported sexual dysfunction side-effects and a general lack of knowledge by primary care physicians.

The study, published in the Journal of Clinical Oncology (JCO), supported the preventative benefits of finasteride, but also indicated that making the decision to prescribe this drug is still a subjective call for clinicians. Simply put, the clinical question of whether or not to give men finasteride might boil down to the adage an ounce of prevention is worth a pound of cure. Lead author, Andrew Vickers, PhD, a statistician at Memorial Sloan Kettering Cancer Center, said that in the study there was about a 2% higher rate of prostate cancer in the placebo group as compared with the men receiving finasteride, which means that you’d need to treat 50 men with finasteride to prevent one prostate cancer.

So, according to Vickers, this isn’t a case of an ounce of prevention being worth a pound of cure. “In order to give finasteride, you’d need to believe that an ounce of prevention is worth 3.2 pounds of cure, and that’s further than most people are willing to go.”

Below are the results and conclusions.

Results: Of 9,058 men, 1,957 were diagnosed with prostate cancer during the 7-year study. For the end point of all cancers, including for-cause and end-of-study biopsies, the optimal strategy is to treat all or nearly all men. To reduce risk of cancers detected through routine care, treating men with PSA > 1.3 or > 2 ng/mL is optimal. For example, treating only men with PSA > 2 ng/mL reduced the treatment rate by 83% and resulted in a cancer rate only 1.1% higher than treating all men.

Conclusion: Clinicians wishing to reduce the risk of any biopsy-detectable prostate cancer should recommend finasteride to all men. Clinicians who believe that it is unnecessary to prevent all cancers, but that preventing those readily detectable by screening would be desirable, would be best off recommending finasteride only to a high-risk subgroup.

How much is prevention worth? For now it seems like the value of finasteride in prostate cancer-as in screening and treatment decisions-a subjective call made between a man and his clinician. But the price can be high, for making the wrong call.