Finasteride benefits report
Study
3040 men with moderate to severe urinary symptoms and enlarged prostate glands were treated with 5 mg finasteride or placebo daily for four years in a randomised, double-blind trial of high quality. It involved clinic visits every four months for symptom scoring and clinical examination. Men with suspected or proven prostate cancer were excluded.
Benefits
Finasteride did its usual job of reducing symptom scores (an average fall of 3 points from a baseline of 15), prostate volume (by 18% on average over four years, compared with a 10% increase with placebo), and increasing urinary flow (by 2 mL/sec from a baseline of 11 mL/sec). But there were also data on men who progressed to acute retention, surgery, and on adverse effects. In the Table we give both the NNTs and NNHs, and the actual rates for benefits and harms.
Finasteride reduced the number of men with acute retention, either spontaneous or precipitated by previous surgery or urinary tract infection, with an NNT of 26. To prevent a man having surgery, the NNT was 18, and for both it was 15. So 15 men with BPH have to be treated with finasteride for four years to prevent one of them having surgery or acute urinary retention. These figures are the same as, or a better than those from an earlier, smaller, trial .
Harms
The report also gives good estimates of possible harms associated with treatment. For instance, in this group of men with a mean age of 64 years at baseline, about 9% became impotent over four years. But 13% became impotent with finasteride, giving a number needed to harm of 23. Other harms are given in the Table. The overall incidence of prostate cancer was 5% in each group in the intensive study.
Comment
This type of information is invaluable in informing men of their options if they have benign prostatic hyperplasia and moderate to severe symptoms. Some will want surgery, some medical treatment, while others will decide that the risks of harm from treatment outweigh the benefits for them. The great thing is that we can now begin to put numbers on the benefits and the harms - which makes it easier to give information to men, and for men to make decisions.