The Gleason score is the most common system doctors use to grade prostate cancer. The grade of a cancer tells you how much the cancer cells look like normal cells. This gives your doctor an idea of how the cancer might behave and what treatment you need.
To find out the Gleason score or Grade Group, a pathologist looks at several samples of cells (biopsies) from your prostate.
The pathologist grades each sample of prostate cancer cells from 3 to 5 based on how quickly they are likely to grow or how aggressive the cells look. You may hear this score being called the Gleason Grade.
Doctors then work out an overall Gleason score by adding together the 2 most common Gleason grades. So for example, if the most common Gleason grade is 3, and the second most common is 4, then the overall Gleason score is 7. Or they might write the scores separately as 3 + 4 = 7. This combined score is also now called the Grade Group.
There are 5 Grade Groups. Grade Group 1 is the least aggressive and Grade Group 5 is the most aggressive.
This is how the Gleason score and Grade Groups match up and what it means:
|Gleason score||Grade Group||What it means|
|Gleason score 6 (or 3 + 3 = 6)||Grade Group 1||The cells look similar to normal prostate cells. The cancer is likely to grow very slowly, if at all|
|Gleason score 7 (or 3 + 4 = 7)||Grade Group 2||Most cells still look similar to normal prostate cells. The cancer is likely to grow slowly|
|Gleason score 7 (or 4 + 3 = 7)||Grade Group 3||The cells look less like normal prostate cells. The cancer is likely to grow at a moderate rate|
|Gleason score 8 (or 4 + 4 = 8)||Grade Group 4||Some cells look abnormal. The cancer might grow quickly or at a moderate rate|
|Gleason score 9 or 10 (or 4 + 5 = 9, 5 + 4 = 9 or 5 + 5 = 10)||Grade Group 5||The cells look very abnormal. The cancer is likely to grow quickly|
It can be difficult to understand what the Gleason score and Grade Group means in your situation. Ask your doctor or specialist nurse if you have any questions about this.
The Gleason score and Grade Groups are important factors that can help your doctor recommend if you need treatment and the type of treatment you need. Other factors include:
- the size of the cancer and whether it has spread (the stage)
- your PSA level
- your age and how well you are
Another important factor is your own preference about the treatments available and their side effects.
Doctors may use these factors to work out your prognosis. This means your likelihood of coming to harm from the cancer if you do or do not have treatment. They balance this against your overall risk of coming to harm from other illnesses.