Even if you’ve just started learning about prostate cancer, you likely have come across terms such as “Gleason score” or “Gleason patterns.” It can all seem a bit confusing, so we wanted to help explain and clarify things.
It begins with a biopsy
Based on your family history and results of other diagnostic tests, your doctor may recommend taking a biopsy of your prostate to check for cancer cells.
Your doctor will use a hollow needle to obtain small samples of prostate tissue called cores. Those samples will be sent to a lab for testing, where a pathologist will examine them under a microscope.1
Identifying Gleason patterns
When the pathologist looks at your samples, they may identify certain cancer cell patterns. These are known as Gleason patterns and are assigned a number (3, 4, or 5) depending on how abnormal the cells look—with 5 being the most abnormal. (1 and 2 are not considered cancer, and so are not used.)1
These numbers for the Gleason patterns are used to calculate the Gleason score.
Calculating the Gleason score
Since prostate tumors often contain more than one pattern of cells, the Gleason score is calculated by combining the numbers for the Gleason patterns of the two largest groups of abnormal cells, creating a score ranging from 6 to 10. So, for example, if the two largest areas of abnormal cells have Gleason pattern numbers of 3 and 4, it would create a Gleason score of 7.1
The importance of the Gleason Score and Grade Groups
A Gleason score represents how much a biopsy sample looks like normal prostate tissue. It also serves as an estimate of how quickly the cancer may grow, and whether it will spread.1
Depending on the Gleason score, patients are assigned to one of five Grade Groups.
| Gleason Patterns | Gleason Score | Grade Group | Prognosis |
|---|---|---|---|
| 3+3 | 6 | 1 | Low-grade cancer. Less aggressive and likely to grow and spread more slowly. If the cancer is small, it could take many years for it to become a problem. And it’s possible that low-grade cancer may never need to be treated. |
| 3+4 | 7 | 2 | Intermediate-grade cancer. Moderately aggressive and likely to grow and spread at a modest pace. While it could be several years before it becomes problematic if the cancer is small, treatment may be needed to prevent problems. |
| 4+3 | 7 | 3 | Intermediate-grade cancer. Moderately aggressive and likely to grow and spread at a modest pace. While it could be several years before it becomes problematic if the cancer is small, treatment may be needed to prevent problems. |
| 4+4, 3+5, 5+3 | 8 | 4 | High-grade cancer. Very aggressive and likely to grow and spread quickly. If the cancer is small, it still may be a few years before it becomes life-threatening. However, immediate treatment is needed to prevent problems. |
| 4+5, 5+4, 5+5 | 9 or 10 | 5 | High-grade cancer. Very aggressive and likely to grow and spread quickly. If the cancer is small, it still may be a few years before it becomes life-threatening. However, immediate treatment is needed to prevent problems. |
Beyond the Gleason Score
While Gleason scores and Grade Groups are a vital part of diagnosis and treatment planning when you have prostate cancer, your doctor will also likely provide you with additional information about tumor stages (also known as “T stages”).
Your doctor will also likely use your Grade Group, PSA level, and tumor stage to place you in a “risk group.”1
It’s a lot of information, but it all helps you and your medical team decide when and how to treat your prostate cancer, along with other factors such as:
- Your overall health and age
- Whether cancer has spread to other organs
- Whether cancer is found in one or both sides of the prostate
- Your desire to have treatment or no treatment at all
Further explanation and helpful patient resources can be found on the National Comprehensive Cancer Network® website.
References
- National Comprehensive Cancer Network (2026). NCCN Guidelines for Patients® Early-Stage Prostate Cancer. Retrieved from https://www.nccn.org/patients/guidelines/content/PDF/prostate-early-patient.pdf