Explaining the Gleason Score to Patients with Prostate Cancer
The Gleason score is a grading system that helps determine how aggressive your prostate cancer is by examining the appearance of cancer cells under a microscope, with scores ranging from 6-10 where higher numbers indicate more aggressive cancer that may require more intensive treatment. 1
What is the Gleason Score?
The Gleason score consists of two numbers that are added together:
- It represents the sum of the two most common patterns of cancer cell growth seen in your prostate tissue sample 1, 2
- Each pattern is graded from 1-5 based on how abnormal the cells look compared to normal prostate tissue
- The first number is the most common pattern, and the second is the next most common pattern
- These two numbers are added together to give a score between 6-10 (scores of 2-5 are rarely used in clinical practice) 1
What the Numbers Mean
- Gleason 6 (3+3): Low-grade cancer that typically grows slowly
- Gleason 7: Intermediate-grade cancer
- 3+4=7: Less aggressive form of intermediate-grade cancer
- 4+3=7: More aggressive form of intermediate-grade cancer 1
- Gleason 8-10: High-grade cancer that may grow and spread more quickly 1
The Grade Group System
To make the Gleason score easier to understand, doctors now often use the Grade Group system (also called ISUP Grade) 1:
| Grade Group | Gleason Score | What it Means |
|---|---|---|
| 1 | 6 or less | Least aggressive |
| 2 | 3+4=7 | Mildly aggressive |
| 3 | 4+3=7 | Moderately aggressive |
| 4 | 8 | More aggressive |
| 5 | 9-10 | Most aggressive |
How the Gleason Score Affects Treatment Decisions
Your Gleason score helps your doctor determine your risk category and treatment options 1:
Low-risk disease (Gleason ≤6, Grade Group 1):
- For life expectancy <10 years: Active surveillance is often recommended
- For life expectancy ≥10 years: Options include active surveillance, surgery, or radiation therapy
Intermediate-risk disease (Gleason 7, Grade Groups 2-3):
- Treatment typically includes surgery or radiation therapy, sometimes with short-term hormone therapy
- The difference between 3+4 and 4+3 matters - the latter has a worse prognosis
High-risk disease (Gleason 8-10, Grade Groups 4-5):
- More aggressive treatment is usually recommended, including surgery or radiation with longer-term hormone therapy
Important Points to Remember
- The order of the numbers matters: 4+3=7 indicates more aggressive cancer than 3+4=7 1
- Recent research shows that there are meaningful differences even within the same Grade Group - for example, Gleason 8 cancers may behave differently than Gleason 9-10 cancers 3
- The Gleason score is just one factor in your overall risk assessment, along with PSA level and clinical stage 1, 2
- Studies show that many patients have difficulty understanding the Gleason system despite its importance in treatment decisions 4
Common Questions
"What does my Gleason score mean for my prognosis?" Higher scores correlate with increased risk of disease progression, metastasis, and mortality 1
"Why is my Gleason score important?" It helps predict how your cancer might behave and guides treatment recommendations 1, 2
"Can my Gleason score change?" Sometimes the score from a biopsy may differ from what's found after surgery, as biopsies sample only portions of the prostate 5
Remember that while the Gleason score is important, it's just one part of your overall cancer assessment. Your doctor will consider this along with other factors to recommend the most appropriate treatment for your specific situation.