Clinical Overview
The Gleason Score is the foundation of prostate cancer grading. Developed by Dr. Donald Gleason, it evaluates the architectural pattern of prostate tumor cells identified on a biopsy. Because prostate cancer often has areas of different grades, a grade is assigned to the two most common patterns, which are then summed.
Pathophysiology & Evidence
Normal prostate tissue has well-defined glands. As cancer becomes more aggressive, it loses this glandular architecture (becoming poorly differentiated).
- Grade 3: The glands are discrete but vary in size and shape.
- Grade 4: The glands are fused or poorly formed.
- Grade 5: There is almost no glandular formation; cells are arranged in solid sheets or single cells.
Formula Breakdown
Total Score = Primary Grade + Secondary Grade
A Gleason score of 6 (3+3) is considered low risk and often managed with active surveillance. A score of 8 or higher indicates high-risk disease requiring aggressive intervention such as surgery or radiation. Modern oncology translates these scores into Grade Groups (1-5) for clearer patient communication.