The American Cancer Society study included more than 10,000 men, aged 50 to 93, who were diagnosed between 1992 and 2011 with localized prostate cancer -- meaning it had not spread beyond the gland. The men provided researchers with information about their physical activity before and after their diagnosis.
Men with the highest levels of exercise before their diagnosis were 30 percent less likely to die of their prostate cancer than those who exercised the least, according to a team led by Ying Wang, senior epidemiologist at the cancer society's epidemiology research program.
More exercise seemed to confer an even bigger benefit: Men with the highest levels of exercise after diagnosis were 34 percent less likely to die of prostate cancer than those who did the least exercise, the study found.
The findings were to be presented Monday at the annual meeting of the American Association for Cancer Research, in New Orleans.
While the study couldn't prove cause-and-effect, "our results support evidence that prostate cancer survivors should adhere to physical activity guidelines, and suggest that physicians should consider promoting a physically active lifestyle to their prostate cancer patients," Wang said in an AACR news release.
The researchers also examined the effects of walking as the only form of exercise. They found that walking for four to six hours a week before diagnosis was also associated with a one-third lower risk of death from prostate cancer. But timing was key, since walking after a diagnosis was not associated with a statistically significant lower risk of death, the study authors said.
"The American Cancer Society recommends adults engage in a minimum of 150 minutes of moderate or 75 minutes of vigorous physical activity per week," Wang said, and "these results indicate that following these guidelines might be associated with better prognosis."
Two experts in prostate cancer care said the findings shouldn't come as a big surprise.
"Physical activity helps all aspects of health," said Dr. Elizabeth Kavaler, a urology specialist at Lenox Hill Hospital in New York City. "This study reinforces that a healthy lifestyle, including exercise, is one of the few aspects of post-cancer outcome that a patient can control."
Dr. Manish Vira, of Northwell Health's Smith Institute for Urology, in New Hyde Park, N.Y., agreed.
The study "adds to the growing body of evidence that regular exercise is associated with better prostate cancer outcomes," he said. "Multiple studies have shown improvements in other cancers as well, including breast, colon and lung cancer."
"Regular exercise improves patients' cardiovascular health, quality of life, and likely, their overall ability to fight disease," Vira added.
Wang stressed that further research is needed to see if the findings might differ by patient age at diagnosis, weight or smoking.More information
The U.S. National Cancer Institute has more about prostate cancer.
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