After a biopsy reveals that cancer is present in the prostate, the Gleason score is a way to describe how aggressive the cancer cells are. If cancer cells are found during your biopsy, the pathologist will use a method known as the Gleason system to describe (or grade) the tissue that make up most of the tumor based on how similar or different it looks compared to normal, healthy prostate tissue.
A number ranging from 3 (looks similar to normal tissue) to 5 (looks very abnormal) is assigned to each of the two patterns the pathologist sees. The score compiles two numbers. The first refers to the most predominant pattern and the second refers to the less predominant pattern.
The Gleason scores are organized into Grade Groups which help make it easier to understand.
Gleason patterns | Gleason score | Grade Group | Risk | Prognosis |
|---|---|---|---|---|
3+3 | 6 | 1 | Low risk | Low-grade cancer is less aggressive and likely to grow and spread very slowly. If the cancer is small, many years may pass before it becomes a problem. Low-grade cancer may never need treatment. |
3+4 | 7 | 2 | Low to intermediate risk | Intermediate-grade cancer is moderately aggressive and likely to grow and spread at a modest pace. If the cancer is small, several years may pass before it becomes a problem. To prevent problems, treatment may be needed. |
4+3 | 7 | 3 | Intermediate risk | |
4+4, 3+5, 5+3 | 8 | 4 | High risk | High-grade cancer is very aggressive and likely to grow and spread quickly. If the cancer is small, a few years may pass before the cancer becomes a life-threatening problem. To prevent problems, treatment is needed now. |
4+5, 5+4, 5+5 | 9 or 10 | 5 | Very high risk |
Staging prostate cancerWhat is my prostate cancer risk group?