The investigators found that among 18,000 men who had been taking Proscar for seven years, there were more than 5,000 deaths. Of these, 2,584 deaths were among men taking Proscar and 2,544 deaths were among men taking placebo.
Over 15 years of follow-up, the survival rate was 78 percent for men in both groups, the study found.
Although men suffering from the most aggressive prostate cancers saw no benefit from Proscar, men with less aggressive cancer taking the drug did have a significant survival advantage, compared to men receiving placebo, the researchers found.
In 2011, the U.S. Food and Drug Administration placed a black-box warning on Proscar for a slight but statistically significant risk that its use could cause aggressive prostate cancer. The drug has several side effects including impotence and loss of interest in sex.
In the new study, the bottom line for the researchers is that "finasteride administration for seven years does not appear to affect mortality but significantly reduces the risk of a prostate cancer diagnosis."
Another expert gave his perspective on the drug.
"At this point, I think that the data is showing that the drug may not be of any significance to patients," said Dr. Louis Kavoussi, chairman of urology at North Shore-LIJ Arthur Smith Institute for Urology in New Hyde Park, N.Y.
However, Proscar may slow the progression of prostate cancer, he said.
"There are individuals who may benefit from being put on this drug and may rest a little bit easier at night knowing that it may not have a negative outcome on their long-term survival," Kavoussi said.
To learn more about prostate cancer, visit the American Cancer Society.
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