Gleason Score & Grade Group Calculator

Enter Calculation

Primary Pattern (most common, 1–5) 1 2 3 4 5

Secondary Pattern (next most common, 1–5) 1 2 3 4 5

Formula

Show calculation steps (1)

1. Grade Group (ISUP 2014 / WHO 2016)

   

   S = Primary + Secondary. Grade Group: 1 if S \u2264 6; 2 if S = 7 and Primary = 3; 3 if S = 7 and Primary = 4; 4 if S = 8; 5 if S = 9 or 10

Results

Gleason Score

3 + 4 = 7

Grade Group 2 (ISUP/WHO)

Primary pattern	3
Secondary pattern	4
Gleason score	7
Grade Group	2

What is the Gleason Score?

The Gleason score is a grading system used by pathologists to describe how aggressive prostate cancer cells appear under the microscope. It is reported as two numbers — the primary pattern (the most common cell pattern in the tissue) plus the secondary pattern (the next most common) — each rated from 1 (looks most like normal tissue) to 5 (most abnormal and aggressive). This calculator adds the two together and converts the result to the modern ISUP/WHO Grade Group. It is intended for educational reference and does not replace a pathologist's report or medical advice.

Gleason patterns 1 to 5 show increasing loss of normal gland structure.

How to use it

Select the primary pattern reported by your pathologist (most prevalent), then the secondary pattern. The calculator instantly shows the total Gleason score (range 2–10, though most clinical scores are 6–10) and the corresponding Grade Group from 1 to 5.

The formula explained

The score is simply Primary + Secondary.

$$\text{Gleason Score} = \text{Primary} + \text{Secondary}$$

The Grade Group simplifies these into five clinically meaningful tiers:

$$\text{Grade Group} = \begin{cases} 1 & S \le 6 \\ 2 & S = 7,\ \text{Primary} = 3 \\ 3 & S = 7,\ \text{Primary} = 4 \\ 4 & S = 8 \\ 5 & S \ge 9 \end{cases} \quad S = \text{Primary} + \text{Secondary}$$

GG1 = score 6 or less; GG2 = \(3+4=7\); GG3 = \(4+3=7\); GG4 = 8; GG5 = 9 or 10. Note that \(3+4\) and \(4+3\) both total 7 but fall into different Grade Groups because the dominant pattern matters.

Advertisement

The primary plus secondary pattern gives the Gleason score, which maps to a Grade Group.

Worked example

Suppose a biopsy shows a primary pattern of 4 and a secondary pattern of 3. The Gleason score is

$$4 + 3 = 7$$

Because the primary pattern is 4 (not 3), this is Grade Group 3 — a more concerning 7 than a \(3+4 = 7\), which would be Grade Group 2.

FAQ

Why are 3+4 and 4+3 different? Both equal 7, but the first number is the dominant pattern. More high-grade (pattern 4) tissue generally means a worse prognosis, so \(4+3\) is Grade Group 3 while \(3+4\) is Grade Group 2.

What is a "good" score? Lower is less aggressive. Grade Group 1 (Gleason 6) is the lowest-risk diagnosable cancer; Grade Group 5 (Gleason 9–10) is the most aggressive.

Is this a diagnosis? No. Only a qualified pathologist and clinician can interpret your full pathology and clinical picture.