Gleason Score Explained: What Your Number Means

This score is one of the most important tools doctors use to understand how aggressive your cancer is, and it plays a major role in determining your treatment plan.

What Is the Gleason Score?

The Gleason score is a grading system used to evaluate prostate cancer cells under a microscope. It tells us how much the cancer cells differ from normal, healthy prostate tissue.

The more abnormal the cells look, the higher the score—and the more aggressive the cancer is likely to be.

How Is the Gleason Score Calculated?

After a prostate biopsy, a pathologist examines the tissue samples and assigns two numbers:

The primary pattern: The most common type of cancer cells seen
The secondary pattern: The second most common type of cancer cells seen

These two numbers are added together to get your total Gleason score.

Example:

3 (most common) + 4 (second most common) = Gleason 7
4 + 3 = also Gleason 7, but slightly more aggressive due to the dominance of pattern 4

Gleason Score Breakdown

Gleason Score	Grade Group	Cancer Behavior
6 (3+3)	Grade Group 1	Low-risk, slow-growing
7 (3+4)	Grade Group 2	Intermediate-risk, mostly slow-growing
7 (4+3)	Grade Group 3	Intermediate-risk, more aggressive
8 (4+4, 3+5, 5+3)	Grade Group 4	High-risk, fast-growing
9–10 (4+5, 5+4, 5+5)	Grade Group 5	Very high-risk, likely to spread quickly

What Does Your Gleason Score Mean for Treatment?

Your Gleason score helps your doctor decide whether to:

Monitor the cancer with active surveillance
Treat the cancer with surgery, radiation, hormone therapy, or a combination

Gleason 6 (Low-Risk):

Cancer is likely to grow very slowly
May not require immediate treatment
Often managed with active surveillance

Gleason 7 (Intermediate-Risk):

Cancer may grow or spread moderately
Treatment may involve surgery or radiation
The breakdown (3+4 vs. 4+3) affects how aggressive it is

Gleason 8–10 (High-Risk):

Cancer is more aggressive and likely to spread
Often requires immediate and combined treatment, such as robotic prostatectomy, radiation, and hormone therapy

Gleason Score vs. PSA Level: What’s the Difference?

PSA (Prostate-Specific Antigen) is a blood test that can detect abnormal activity in the prostate.
Gleason score is based on actual cancer cells found in a biopsy.

Together, these two tools help determine your cancer stage and guide your care.

Can the Gleason Score Change Over Time?

Yes. If you’re on active surveillance, your cancer may become more aggressive. That’s why Dr. Samadi closely monitors:

PSA trends
Repeat MRIs
Follow-up biopsies

If your Gleason score increases, treatment can begin before the cancer spreads.

Why Work With Dr. David Samadi?

With thousands of successful surgeries and decades of experience, Dr. Samadi is one of the world’s leading experts in:

Accurate diagnosis and risk stratification
Robotic prostatectomy for intermediate/high-risk cancers
Individualized care based on Gleason score, PSA, and personal goals

You won’t just get a number—you’ll get a clear plan of action.

Need Help Understanding Your Gleason Score?

If you've recently been diagnosed with prostate cancer, Dr. Samadi can explain exactly what your Gleason score means—and help you decide the best path forward.

Schedule a consultation today
Call now: 212-365-5000