Finasteride shows long-term safety, efficacy for prostate cancer prevention

Goodman P, et al. N Engl J Med. 2019;doi:10.1056/NEJMc1809961.

In the Journal Plus

Finasteride safely and effectively prevented prostate cancer, despite previous findings that suggested the drug increased the risk for high-grade disease, according long-term data published in The New England Journal of Medicine.

The latest results report mortality over 2 decades among men in the Prostate Cancer Prevention Trial, which previously found that finasteride reduced risk for prostate cancer by 24.8% compared with placebo.

However, trial results also showed that the drug increased the number of high-grade prostate cancers, leading to a warning label from the FDA. Although additional data showed finasteride improved detection of prostate cancer and high-grade prostate cancer by improving the performance characteristics of PSA testing, digital rectal examination and the prostate biopsy — which could explain the conflicting original results — questions regarding the risk of the drug persisted.

Finasteride, a 5-alpha-reductase inhibitor, also is used to treat lower urinary tract problems and male pattern baldness.

“The men most likely to benefit are those we see in the study — they are 55 years or older and are undergoing PSA testing,” Ian M. Thompson Jr., MD, chair of the genitourinary cancer committee for SWOG Cancer Research Network and president of CHRISTUS Santa Rosa Hospital Medical Center, told HemOnc Today. “The magnitude of the benefit may be greater in men who are at higher risk for prostate cancer, that being a man with a family history or an African-American man. ... But what we found in the original study is that all men — regardless of family history, race, ethnicity and so forth — have a risk reduction.”

Researchers of the trial randomly assigned 18,882 men — enrolled from 1993 to 1997 — to receive finasteride or a placebo for 7 years.

At median follow-up of 18.4 years, 42 men in the finasteride group and 56 men in the placebo group had died of prostate cancer.

The 25% lower risk for prostate cancer death with finasteride was not statistically significant (HR = 0.75; 95% CI, 0.5–1.12).

However, Thompson said the results eliminate concerns about the possible risk for more aggressive cancers with finasteride, which he described as an inexpensive and reliable prostate cancer prevention drug.

He said that he is unaware of a clear process that would take the warning label off the drug.

“But it’s not just changing the warning. It’s also putting in the label that this drug results in an unequivocal reduction in the risk for cancer,” Thompson told HemOnc Today. “This is really a big deal. ... If we had known this at the time the study was originally published, my suspicion is that many or most men who are [aged] 55 years or older would be taking this medication. But because it had a stain on it ... it’s kind of like a sticky fact. The trick will be helping the community get rid of that sticky fact and go back to this original discovery.

“This is the most common cancer in men,” Thompson added. “If men at risk for prostate cancer took this, we could eliminate 40,000 to 50,000 prostate cancer [diagnoses] a year, and that’s a huge deal from a cost and suffering standpoint.” – by John DeRosier

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Ian M. Thompson Jr., MD, can be reached at:

Disclosures: The NCI and NIH funded this study. Thompson reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.

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