Gleason Score Calculator
For Health Professionals
Calculate Prostate Cancer Aggressiveness
Select the primary and secondary Gleason grades from the biopsy report:
Results
Clinical Interpretation
The Gleason Score is a grading system used to describe how aggressive a prostate cancer is, based on how the cancer cells look under the microscope. It was first developed by Dr. Donald Gleason in the 1960s and remains a central part of prostate cancer staging and treatment planning, although it is now often paired with the newer ISUP Grade Group (1–5) system. Wikipedia+1
How the Gleason Score is calculated
When a prostate biopsy is taken, a pathologist looks at the cancer cells and assigns patterns from 3 to 5 (patterns 1–2 are no longer used for cancer in modern practice): Prostate Cancer UK+1
- Pattern 3 – cancer cells still form reasonably well-organized glands; less aggressive
- Pattern 4 – glands are fused, cribriform, or poorly formed; more aggressive
- Pattern 5 – sheets of cells with no glands; very aggressive
The pathologist then: Prostate Cancer UK+1
- Identifies the most common pattern (primary grade).
- Identifies the highest other pattern (secondary grade).
- Adds them together: Gleason score = primary grade + secondary grade
Example: predominant pattern 3 and secondary pattern 4 → 3 + 4 = 7.
Modern pathology reports usually give:
- The Gleason pattern combination (e.g. 3+4 or 4+3)
- The total score (6–10 for cancer)
- The corresponding ISUP Grade Group (1–5): pathology.jhu.edu+3Cancer Research UK+3Macmillan Cancer Support+3
| Gleason | Typical pattern | ISUP Grade Group | Broad meaning |
|---|---|---|---|
| 6 (3+3) | Pattern 3 only | 1 | Low-grade, usually slow-growing |
| 7 (3+4) | Mostly 3, some 4 | 2 | “Favourable” intermediate-risk |
| 7 (4+3) | Mostly 4, some 3 | 3 | “Unfavourable” intermediate-risk, more aggressive than 3+4 |
| 8 (e.g. 4+4, 3+5, 5+3) | High-grade | 4 | High-risk, aggressive |
| 9–10 (e.g. 4+5, 5+4, 5+5) | Very high-grade | 5 | Very high-risk, very aggressive |
In general, higher Gleason scores and Grade Groups mean more aggressive cancer, a higher chance of spread, and stronger consideration of active treatment rather than surveillance. Cancer.org+3Cancer.org+3Macmillan Cancer Support+3
However, treatment decisions never rely on Gleason score alone: PSA level, MRI findings, clinical stage, number of positive cores, patient age, comorbidities, and preferences are all critical.
