A Gleason score of 8 to 10 is indicative of high-grade prostate cancer with cells that are undifferentiated or poorly differentiated and that is likely to grow more rapidly than other prostate cancers, according to Cancer.Net. Patients with high Gleason scores usually require more intensive treatment.
Gleason scores are based on a visual microscopic examination of biopsied tissue by a pathologist in a lab following a prostate biopsy, notes Cancer.Net. The tissue is compared to normal healthy tissue to determine its Gleason score, with emphasis given to main cell growth pattern. This scoring system is the most widely used in prostate cancer treatment.