What is a Gleason score?
If you have prostate cancer, your Gleason score is one factor healthcare providers consider to develop your treatment plan.
Your score reflects what providers learned about your cancer after examining tissue samples from your prostate cancer biopsy. They looked for patterns of normal and abnormal cells, noting where your cells look more like cancerous cells and where they look more like healthy cells.
Then they graded each piece of the pattern on a 3 to 5 scale. Pattern pieces with cancer cells that look like healthy cells were graded low. Pieces with cancer cells that don't look like healthy cells get high grades.
Providers add those scores to set an overall Gleason score between 6 and 10. They might refine their analysis by classifying your cells by group, with Gleason scores listed in grade groups 1 to 5.
What is a normal Gleason score for prostate cancer?
Your Gleason score doesn't rank potential ranges like ranges set for elevated PSA (prostate-specific antigen) tests. Instead, providers break Gleason scores into three categories:
- Gleason 6 or lower: The cells look similar to healthy cells, which is called well differentiated.
- Gleason 7: The cells look somewhat similar to healthy cells, which is called moderately differentiated.
- Gleason 8, 9 or 10: The cells look very different from healthy cells, which is called poorly differentiated or undifferentiated.
What are grade groups?
Healthcare providers established grade groups to clarify the Gleason score system. Those grade groups are:
- Grade Group 1 = Gleason 6 (or fewer).
- Grade Group 2 = Gleason 3+4=7.
- Grade Group 3 = Gleason 4+3=7.
- Grade Group 4 = Gleason 8.
- Grade Group 5 = Gleason 9-10.
What is a bad Gleason score for prostate cancer?
Gleason scores aren't good or bad, per se. They predict how quickly your prostate cancer might grow. Tumors with higher Gleason scores are likely to grow quickly. And Gleason scores aren't the only factors healthcare providers consider when creating your treatment plan.
What other factors do healthcare providers consider?
Providers consider the results of other tests and additional biopsy information. For example, when you had your biopsy, your healthcare provider obtained several samples or cores from your prostate. They checked how many cores contained cancer and whether most of the cells in the cores were cancerous cells.
Other factors may include:
- Blood PSA level.
- Digital rectal exam results.
- Imaging test results like ultrasound, magnetic resonance imaging (MRI) or positron emission tomography (PET) scan.
- Whether cancer was found in both sides of your prostate.
- Whether cancer has spread outside of your prostate.
A note from Cleveland Clinic
Healthcare providers use Gleason scores to learn more about your prostate cancer. But numbers don't tell the whole story about your prostate cancer. That story starts with your treatment plan and understanding what to expect from your treatment. Think of your Gleason score and other analysis as the next chapter in your story. Talk to your healthcare provider any time you have questions about your Gleason score or any other test result. They'll be glad to help you understand what the numbers mean.