TUESDAY, May 20 (HealthDay News) -- Men with advanced prostate cancer that hasn't spread beyond the gland should receive radiation therapy as soon as the prostate has been removed, a new long-term study says.

"What we are showing today is that there is a significant difference between men who were treated with radiation and those who weren't," study co-author Dr. Gregory P. Swanson, of Cancer Care Northwest Spokane, Wash., said during a Tuesday teleconference at the American Urological Association annual meeting, in Orlando, Fla.

"We found that overall survival increased among men who had radiation therapy compared with those who did not," he said.

For the study, 413 men with advanced localized prostate cancer were assigned to receive radiation soon after surgery to removed their prostate, or no radiation until their blood levels of prostate-specific antigen rose. Prostate-specific antigen (PSA) is a protein produced by the cells in the prostate; because PSA can be used to detect disease, it is sometimes called a biological marker or tumor marker, according to the National Cancer Institute.

The men were checked every three months for one year, every six months for two years, then annually until death. The examinations included PSA measurements and bone scans if warranted, the researchers said.

The researchers found that radiation therapy after prostatectomy (removal of the prostate) significantly reduced the recurrence of prostate cancer during the 11.5 year follow-up period. There was significant improvement in disease-free survival and overall survival, with survival rates increased by almost two years, the researchers said.

However, the men who did undergo radiation therapy reported more side effects, such as incontinence and impotence, than men who didn't receive the therapy, which is to be expected, the researchers noted.

"Here we had a study that shows that radiation improves survival," said study co-author Dr. Ian M. Thompson Jr., of the Division of Urology and the Department of Surgery at the University of Texas Health Science Center at San Antonio. "More importantly, you live longer, with less risk of having metastatic disease. To improve survival by almost two years is extraordinary."

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.

SOURCES: Bruce Roth, M.D., professor, medicine and urologic surgery, Vanderbilt University, Nashville, Tenn.; May 20, 2008, teleconference with Gregory P. Swanson, M.D., Cancer Care Northwest Spokane, Wash.; Ian M. Thompson Jr., M.D., Division of Urology, Department of Surgery, University of Texas Health Science Center at San Antonio; May 20, 2008, American Urological Association annual meeting, Orlando, Fla.

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