A new study shows that walking briskly for at least three hours a week can slow or even prevent the spread of prostate cancer. The study found that the only way to bring about this effect was to walk briskly. If prostate cancer patients walked at an easy pace, they would not receive this effect. Researchers at the University of California, San Francisco, studied 1,455 men diagnosed with prostate cancer that had not yet begun to spread. The researchers assessed the patients’ level of physical activity two years after being diagnosed with cancer and receiving initial treatment. They found 117 cases of prostate cancer-induced cancer recurrence, bone tumors and death. And those patients who walked briskly for at least three hours a week had a 57 percent reduction in the rate of spread of their disease than those who walked slowly and spent less time exercising. The study, published in the recent issue of the journal Cancer Research, says the findings add new evidence to the theory that regular exercise can combat many diseases, such as heart disease and certain cancers. The researchers noted that patients who engaged in brisk walking after being diagnosed with the disease appeared to delay or even prevent the spread of the disease.