The men who got radiation therapy had more than 50 percent less need for hormone therapy, Thompson said.
Given the results of this trial, patients should receive radiation therapy immediately after prostate surgery and not wait for their PSA levels to start rising, he said.
"Perhaps the most commonly used treatment is to watch these patients until their PSA starts to go up," Thompson said. "At least from this randomized clinical trial, the evidence would suggest that the cure rate is less, survival is less with that approach."
Dr. Bruce Roth, a professor of medicine and urologic surgery at Vanderbilt University, said radiation procedures have changed since the study began, so the findings may not be as applicable now.
"Now, we routinely give significantly higher doses of radiotherapy," he said, adding that higher doses are probably more effective, but they also increase side effects.
"Offering radiation therapy to all patients with advanced prostate cancer is not the right thing to do," Roth said. "There are patients who are more likely to have a local-only recurrence, and therefore benefit from radiation therapy. We have become a little more sophisticated in terms of whom to offer this therapy to."
More information
Learn more about prostate cancer from the National Cancer Institute.
