For African American men, the risk of dying from low-grade prostate cancer is double that of men of other races, a new study has found. But, despite the difference, the risk is still small. When a man is diagnosed with prostate cancer, the disease is given a grade, or score, based on how abnormal (or aggressive) the cancer cells look under a microscope. This system for assessing the aggressiveness of a prostate tumor is called the Gleason score. Prostate cancer with a Gleason score of 6 is considered low grade, meaning it is less likely to grow and spread than cancer with a higher score (7 to 10). The vast majority of men diagnosed with localized, low-grade prostate cancer will die of something other than prostate cancer. But, according to the new findings, doctors may be “underestimating the risk” of death from low-grade prostate cancer in African American men, said lead investigator Franklin Huang, M.D., Ph.D., of the University of California, San Francisco. The study findings, published December 18 in JAMA, are consistent with other reports that have identified racial differences in the biology and presentation of low-grade prostate cancer, said Howard Parnes, M.D., chief of the Prostate and Urologic Cancer Research Group in NCI’s Division of Cancer Prevention, who was not involved in the study. This body of evidence, Dr. Huang added, supports the idea that certain biological factors may make low-grade prostate cancer more likely to grow and spread in African American men than in men of other races.