The medications, known as NSAIDs, are thought to reduce inflammation of the prostate that has been linked to development of cancer cells, the study's authors report in the journal Mayo Clinic Proceedings.
The five-year study of 1 362 men found that four percent of those who took the painkillers developed prostate cancer, versus nine percent of those in the non-treated group. The older the patient, the more likely he was to be helped by the drug, the authors say.
But the researchers issued a strong word of caution, noting that prolongued use of anti-inflammatory drugs can lead to serious problems in the stomach and liver.