After a prostate biopsy, your results will include a Gleason score and a Grade Group. These numbers are among the most important pieces of information in planning treatment. They describe how the cancer cells look under the microscope and give a good idea of how likely the cancer is to grow and spread.
How grading works
A pathologist examines the biopsy samples and looks at the pattern of the cancer cells. Cells that look and arrange themselves much like normal prostate tissue are less likely to grow quickly. Cells that look very disorganised are more likely to behave aggressively.
Each pattern is given a grade from 3 to 5. Grades 1 and 2 are no longer used in practice.
How the Gleason score is made
The pathologist identifies the most common pattern and the second most common pattern in the samples. The two grades are added together to give the Gleason score.
For example:
- 3 + 3 = 6: both patterns are grade 3
- 3 + 4 = 7: mostly grade 3, with some grade 4
- 4 + 3 = 7: mostly grade 4, with some grade 3
Although 3 + 4 and 4 + 3 both add up to 7, they are different. A cancer that is mostly grade 4 tends to be more aggressive.
The Grade Group system
Because Gleason scores can be confusing, a simpler system called Grade Groups is now used alongside them:
- Grade Group 1 (Gleason 6): low grade, usually slow-growing.
- Grade Group 2 (Gleason 3 + 4): mostly low grade with a small aggressive part.
- Grade Group 3 (Gleason 4 + 3): more of the aggressive pattern.
- Grade Group 4 (Gleason 8): high grade.
- Grade Group 5 (Gleason 9 or 10): the most aggressive.
Prostate Cancer UK has clear diagrams showing how the two systems match.
What the grade means for treatment
The grade is one part of a wider risk assessment that also includes PSA level and the stage of the cancer. Together, these place a cancer in a risk group, as set out in NICE guidance on prostate cancer.
Grade Group 1: many men can be monitored with active surveillance rather than treated straight away.
Grade Group 2: active surveillance may still be an option for some men, while others choose treatment.
Grade Groups 3 to 5: treatment is usually recommended, such as robotic prostatectomy or radiotherapy, sometimes with hormone therapy.
Can the grade change?
Yes. A biopsy samples only part of the prostate, so the grade found after surgery, when the whole gland is examined, can sometimes be higher or lower. Men on active surveillance also have regular checks, and a later biopsy may show a change in grade.
Other details in your report
Your biopsy report may also mention:
- how many samples contained cancer
- how much of each sample was affected
- whether there was any cribriform pattern or intraductal cancer, features that may suggest more aggressive behaviour
- whether the cancer appeared to touch the nerves around the prostate
These details help your specialist refine the advice. Our article on nerve-sparing robotic prostatectomy explains why nerve involvement matters for surgery.
Making sense of your results
It is normal to find these numbers confusing at first, and nobody expects you to remember every detail after one appointment. Write down your Gleason score, Grade Group, PSA and stage, and bring them to your next appointment. Our guide to questions to ask your surgeon can help you prepare, and our prostate cancer page explains the treatment options.
Professor Prokar Dasgupta can review your biopsy results and talk through what they mean for you at The London Clinic. Please contact the clinic to arrange a consultation.