After an average follow-up of about 13 years, 14.6 percent of the men who had undergone surgery had died, versus 20.7 percent in the watchful waiting group, a 38 percent reduced risk.
The benefit was primarily seen among men younger than 65 and the authors estimated that seven men under the age of 65 and 8 over the age of 65 would need to be treated to save one life.
There was also a benefit in men whose tumors had low-risk characteristics.
Men whose cancer had moved outside of the prostate gland and who underwent removal of the prostate had a seven times higher risk of dying than men whose tumors hadn't spread.
Radical prostatectomy can come with a price -- including erectile dysfunction, urinary incontinence and even bowel incontinence -- although these effects are not as common as techniques improve. A nerve-sparing radical prostatectomy, for example, may be able to prevent erectile dysfunction.
Also, the men in this study were diagnosed only after they had symptoms, unlike the majority of men in the United States, Greenberg said.
"The advantage of screening is that men are more likely to be cured of cancer but they also have a greater chance of not succumbing to the consequences of the surgical complications, whether [those] be erectile dysfunction or urinary incontinence," Greenberg said.
Also, he said, erectile dysfunction can also be a factor of aging and can be treated in most cases.
But much remains to be known about how best to treat different types of prostate cancer.
"The management of early stage prostate cancer continues to require further randomized controlled studies, which are underway, to determine the true benefit of treatment versus expectant management," said Dr. Marc Danziger, an attending urologist at Lenox Hill Hospital in New York City,
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