A 50-year-old male presents to your office after reading an article on the Internet stating that a recent study showed that the drug finasteride can prevent prostate cancer. He asks you to prescribe this medication for him. You review the article and find the following information: a randomizedcontrolled trial of men over the age of 55 with normal prostate-specific antigen (PSA) readings was performed comparing finasteride and a placebo. At the end of the study, 18% of the men in the finasteride group and 24% of the men in the placebo group had developed prostate cancer.
Further review of the article reveals that 6.4% of the men in the finasteride group and 5.1% in the placebo group developed high-grade prostate cancers.
How many men need to take finasteride in order to have one excess case of high-grade prostate cancer (number needed to harm [NNH])?