Researchers at the University of California, San Francisco and the Harvard School of Public Health followed 1,455 men who had been diagnosed with early-stage prostate cancer.
The study shows that survivors who walk at a pace of at least 3 miles per hour for three hours or more per week were 57% less likely to develop the biochemical markers of cancer recurrence or to need a second round of treatment for their disease.
"The important point was the intensity of the activity," Erin Richman, ScD, a post-doctoral fellow at University of California, San Francisco, says in a news release. "The walking had to be brisk for men to experience a benefit."
She says the results of the study suggest a way for men who have prostate cancer to do something to improve their prognosis and stay well.
The study is published in the June 1 edition of Cancer Research.
Another study published earlier this year by June Chan, ScD, of University of California, San Francisco, along with researchers at Harvard, also showed that physical activity after diagnosis seemed to reduce disease-related death in a distinct group of men with prostate cancer.
The new study supports that finding and was the first to focus on the effect of exercise after diagnosis on early indications of progression of the disease, such as a rise in prostate-specific antigen (PSA) blood levels.
"Our work suggests that vigorous physical activity or brisk walking can have a benefit at the earlier stages of the disease," says Chan in the news release.
The participants in the study were a subset of a larger group of 14,000 men with prostate cancer enrolled in a long-term, nationwide prostate cancer registry project, known as the Cancer of the Prostate Strategic Urologic Research Endeavor. It's led by Peter Carroll, MD, MPH, chair of the urology department at University of California, San Francisco and one of the study's authors.
Benefits of Physical Activity
The researchers also report that the benefit of physical activity in their study was independent of the participants' age at diagnosis, type of treatment, and clinical features of their disease when first detected.
Chan says she would recommend walking for all men with prostate cancer, but stresses the walking must be brisk and not leisurely.
"Our results suggest that it is important to engage in exercise that gets your heart rate up a bit," she says.
The 1,455 men observed by the researchers had been diagnosed with prostate cancer that had not spread beyond the prostate gland. They reported their physical activity by questionnaire about 27 months after their original diagnosis and before evidence suggested the cancer had recurred or that there may be a need for additional treatment.
The researchers say they recorded 117 events, including elevations of PSA, secondary treatments, bone metastasis, and prostate cancer-specific death.
"The benefit from walking truly depended on how quickly you walked," Richman says. "Walking at any easy pace did not seem to have any benefit."
Prostate cancer is the second leading cause of cancer death among men. More than 2.2 million men in the U.S. are living with prostate cancer and 217,000 new cases were reported in 2010. Last year, 32,050 men died from prostate cancer.
Stephen M. Schwartz, PhD, senior editor of Cancer Research and a scientist at the Fred Hutchinson Cancer Research Center, says the new study is important because research on the role of physical activity in prostate cancer has been somewhat limited.
"We have had some studies that show a reduced risk of developing prostate cancer, but this is strong evidence of a benefit after someone is diagnosed," he says in a news release.