These researchers studied a group of 771 men, ages 55 to 75, who were diagnosed with localized prostate cancer, during the years from 1971 to 1984. All patients in this group received conservative management, meaning no surgery or radiation; they had only hormonal therapy. Fifteen years after diagnosis, the investigators found that prostate cancer mortality was dramatically affected by the biopsy grade of the cancer at diagnosis, regardless of the man's age.

After 15 years, men with high grade prostate cancer (Gleason scores greater than 7), faced a significant risk of death from prostate cancer, even when diagnosed at age 75. Men with lower grade cancers (Gleason score 2 to 6) faced a more modest risk of death in 15 years, even when diagnosed at a young age.

These researchers believe that this data should assist men with treatment decision analysis, and allow clinicians to evaluate relative treatment efficacy.