Brisk walking might be able to help men who have been diagnosed with early-stage prostate cancer to cut their risk that the disease will progress, a new study has found.

The finding suggests that there is something that men who have prostate cancer can do to improve their prognosis, rather than just wait to see if the disease worsens.

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. All the men had cancer that had not spread beyond the prostate.

The men reported their physical activity by questionnaire about 27 months after their original diagnosis.

Among the group, there were 117 "events," including an elevation of prostate-specific antigen (PSA) blood levels, which is an indication of cancer progression; the need for secondary treatments; spread of the cancer to the bone; or death directly related to the prostate cancer.

The researchers found that the men who walked at a pace of at least five kilometres per hour for three hours or more per week were 57 per cent less likely to die or to develop markers of cancer recurrence or the need for a second round of treatment for their disease.