Researchers followed 381 people to “identify predictors of time to prostate specific death following external radiation therapy.” “The results of this study give us a better understanding of what form of treatment will extend a patient’s life to a point where he’s more likely to die from causes other than prostate cancer,” says Anthony D’Amico, research leader and an associate professor of radiation oncology at Harvard Medical School. He and his colleagues divided the men into three groups: high, intermediate, and low risk of prostate cancer death. The first thing they checked was the amount of PSA, or prostate-specific antigen, in the men’s blood. The body secretes excess amounts of this protein in response to prostate cancer. The higher its level, the more cancer is present. After treatment, by radiation or surgery, doctors closely monitor PSA levels. Men whose PSA levels rise rapidly do a lot worse than others. D’Amico and his team found that a doubling of PSA scores in one year or less is almost a sure predictor of death for those who received external radiation. Of 18 men in his study who showed such a rise, 17 of them died because the cancer spread to their bones.