About this page. This is a plain English summary of how a prostate biopsy is graded and what the result means. It does not replace medical advice from your own doctor or specialist.
For full information and references, please read the detailed page.
What happens after a biopsy?
During a prostate biopsy, up to about 14 fine cores of tissue are taken from different parts of the prostate. The cores are sent to a pathologist, who looks at them under a microscope to check for cancer.
If cancer is found, the pathologist also reports on how aggressive it looks. That is what "grading" means.
The Gleason score, in plain English
Most other cancers are graded by looking at how unusual the cells appear. Prostate cancer is graded a bit differently: the pathologist looks at the pattern of the prostate glands in the sample.
A pathologist named Donald Gleason worked out the system, which is why it is called the Gleason score. It works like this:
- The pathologist looks at the most common pattern of glands in the cancer, and gives it a score out of 5.
- They then look at the second most common pattern, and give that a score out of 5 too.
- The two scores are added together to give a number out of 10.
So a result like Gleason 4 + 3 = 7 means: the most common pattern was a 4 out of 5, the second most common was a 3 out of 5, and the total is 7. That is why people often talk about a "Gleason 7" cancer.
In general:
- A lower Gleason score (e.g. 6) suggests a less aggressive cancer.
- A higher Gleason score (e.g. 8, 9, or 10) suggests a more aggressive cancer that is more likely to need treatment.
Other things on the report
The Gleason score is the most important number, but the pathologist also reports on:
- Number of positive cores. For example, "12 of 14 cores positive" is very different from "1 of 14 cores positive". It tells the urologist how widespread the cancer is in the prostate.
- Percentage of each core involved. A core that is 90% cancer is more concerning than one that is 5%.
- Perineural invasion and vascular invasion. Whether the cancer has touched small nerves or blood vessels in the sample. This adds extra information but is less central to the decision.
Why the grade matters
The Gleason score and the rest of the report together give a picture of how aggressive the cancer is and how widespread it is in the prostate. That picture is what guides the next step:
- A small, low-grade cancer may be safely watched on active surveillance.
- A larger or higher-grade cancer is more likely to need active treatment such as surgery or radiotherapy.
Important things to know
- The Gleason score is a number, but it does not work like exam marks. A "Gleason 6" is still cancer, even though it is at the lower end of the scale.
- Pathologists are highly trained, but grading is still partly a matter of judgement. Some cases sit on the border between two grades, and a second opinion on the slides is reasonable when a major decision is being made.
- A biopsy only reports on the small samples that were taken. The grade in another part of the prostate could be slightly different.
- The Gleason score is one part of the picture. The PSA, the MRI scan, the rectal examination, and the staging tests all matter as well.
What you can do next
- Read the full detailed page with references.
- Short version: staging, which combines with the Gleason score.
- Short version: treatment options.
- Request a second opinion on a biopsy result.
- Call 02 8382 6980 to make an appointment.