Quick Answer: What Does the Gleason Score Mean?
The Gleason score is a pathology grade describing the microscopic architecture of prostate cancer. In contemporary practice, pathologists also report an easier-to-understand ISUP Grade Group from 1 to 5.
The most important modern conversion is:
- Grade Group 1: Gleason 3+3=6
- Grade Group 2: Gleason 3+4=7
- Grade Group 3: Gleason 4+3=7
- Grade Group 4: Gleason 8 (4+4, 3+5 or 5+3)
- Grade Group 5: Gleason 9–10 (4+5, 5+4 or 5+5)
Grade is not the same as stage. Gleason/Grade Group describes aggressiveness under the microscope; TNM stage describes how far the cancer has spread.
A treatment decision should never be based on the Gleason score alone. Doctors combine Grade Group with PSA, clinical stage, MRI/PSMA imaging when appropriate, biopsy burden, age, health and patient preferences.
What Is the Gleason Grading System?
The Gleason system is a microscopic grading method used by pathologists to assess the architecture of prostate adenocarcinoma.
A pathologist examines prostate tissue obtained by:
- needle biopsy;
- transurethral or other prostate tissue sampling in unusual circumstances; or
- radical prostatectomy.
The pathologist looks at how closely the cancer glands resemble normal prostate glands and assigns an architectural Gleason pattern.
Gleason Pattern Is Not the Same as Gleason Score
This is one of the most common sources of confusion.
A Gleason pattern is a microscopic pattern graded from 3 to 5 in contemporary prostate-cancer practice.
The Gleason score combines two patterns.
For example:
Gleason 3 + 4 = 7
means that pattern 3 is the dominant pattern and pattern 4 is the next most important higher-grade pattern represented in the biopsy according to modern reporting rules.
Why Don’t Modern Biopsy Reports Usually Start at Gleason 2?
The original Gleason system used patterns 1 through 5 and theoretically allowed total scores from 2 to 10.
But modern pathology changed.
EAU explains that the 2005 and 2014 International Society of Urological Pathology (ISUP) consensus revisions effectively eliminated Gleason patterns 1 and 2 from contemporary prostate-cancer grading.
As a result, the lowest score ordinarily assigned to cancer found on a modern prostate needle biopsy is:
Gleason 3+3=6 — Grade Group 1.
What Do Gleason Patterns 3, 4 and 5 Mean?
Pattern 3
Cancer glands remain relatively well formed and separate from one another.
Pattern 3 is the least aggressive pattern routinely diagnosed as prostate cancer on modern biopsy.
Pattern 4
The normal gland architecture is more disrupted.
Pattern 4 includes several abnormal architectures such as fused, poorly formed and cribriform glands.
The amount and type of pattern 4 matter because even two cancers with the same Grade Group 2 label can have different biological behavior.
Pattern 5
Pattern 5 has the least gland formation and the most poorly differentiated architecture.
It is associated with more aggressive cancer behavior.
How Is the Gleason Score Calculated?
For a typical biopsy containing two cancer patterns, the score is formed by adding two Gleason patterns.
Examples:
- 3 + 3 = 6
- 3 + 4 = 7
- 4 + 3 = 7
- 4 + 4 = 8
- 4 + 5 = 9
- 5 + 5 = 10
Modern pathology rules are more detailed when three patterns are present, particularly on biopsy. The highest-grade component can influence the reported score even if it is not the second-most-common component.
Why Is Gleason 3+4 Different From 4+3?
Although both add up to 7, they are not biologically equivalent.
3+4=7 means pattern 3 predominates and pattern 4 is less extensive.
4+3=7 means the more aggressive pattern 4 predominates.
That is why modern Grade Groups separate them:
- 3+4=7 → Grade Group 2
- 4+3=7 → Grade Group 3
Grade Group 3 generally carries a greater risk of recurrence and progression than Grade Group 2.
Modern Grade Group 1–5 System
| ISUP Grade Group | Gleason score | General interpretation |
|---|---|---|
| Grade Group 1 | 3+3=6 | Lowest-grade contemporary prostate cancer; often indolent when disease volume and other risk factors are favorable. |
| Grade Group 2 | 3+4=7 | Mostly pattern 3 with some pattern 4; often favorable-intermediate risk when PSA, stage and biopsy extent are favorable. |
| Grade Group 3 | 4+3=7 | Pattern 4 predominates; more aggressive than Grade Group 2 and generally unfavorable-intermediate risk when localized. |
| Grade Group 4 | 4+4=8, 3+5=8 or 5+3=8 | High-grade disease with substantially increased progression risk. |
| Grade Group 5 | 4+5=9, 5+4=9 or 5+5=10 | Highest-grade category; aggressive biology and high risk of progression/metastasis, although stage still must be assessed separately. |
What Does “Grade Group 1” Mean?
Grade Group 1 corresponds to Gleason 3+3=6.
When combined with:
- PSA below 10 ng/mL;
- clinical stage cT1–cT2 disease according to the risk-classification system being used;
- small-volume cancer;
- favorable MRI findings; and
- no important adverse histologic features
it often represents low-risk prostate cancer.
For many suitable men, active surveillance is preferred over immediate surgery or radiation.
What Does Grade Group 2 Mean?
Grade Group 2 means Gleason 3+4=7.
The prognosis varies considerably depending on:
- how much pattern 4 is present;
- number and percentage of biopsy cores involved;
- PSA;
- clinical stage;
- MRI findings;
- whether cribriform/intraductal cancer is present; and
- other pathology features.
EAU allows active surveillance for highly selected low-volume Grade Group 2 cancers—for example, small amounts of pattern 4, favorable PSA/stage and low disease volume—provided the patient accepts a somewhat greater progression risk.
Other Grade Group 2 cancers are treated with surgery or radiation.
What Does Grade Group 3 Mean?
Grade Group 3 is Gleason 4+3=7.
Because pattern 4 predominates, this is more concerning than Gleason 3+4.
EAU specifically recommends that Grade Group 3 disease should be excluded from active-surveillance protocols.
When localized, definitive treatment usually involves:
- radical prostatectomy in appropriate surgical candidates; or
- radiotherapy, commonly with short-term ADT depending on the complete risk profile.
What Do Grade Groups 4 and 5 Mean?
Grade Groups 4 and 5 represent high-grade prostate cancer.
Even if imaging suggests disease is still localized, these cancers have a substantially higher risk of:
- extraprostatic extension;
- lymph-node involvement;
- biochemical recurrence;
- metastatic progression; and
- prostate-cancer death.
But high grade still does not automatically equal stage IV.
A Grade Group 5 tumor can be localized, locally advanced or metastatic. That must be determined through staging.
Grade Is Not Stage
| Term | What it describes | How it is determined |
|---|---|---|
| Gleason / Grade Group | Microscopic tumor architecture and biological aggressiveness | Pathologist examines tissue |
| TNM stage | Extent of tumor, lymph-node involvement and distant metastasis | Clinical exam, imaging, surgery/pathology where applicable |
| PSA | Blood biomarker reflecting prostate activity and helping estimate risk | Blood test |
| Risk group | Combined estimate used to guide treatment | Grade Group + PSA + clinical stage, with modern imaging/pathology refinements |
Read our complete guide to prostate cancer stages.
What Are the Current EAU Risk Groups?
Modern risk classification combines Grade Group with PSA and clinical stage.
| EAU risk category | Typical defining features | General implication |
|---|---|---|
| Low risk | Grade Group 1 AND PSA <10 ng/mL AND localized cT1–2 disease under the EAU classification. | Active surveillance is often preferred when otherwise suitable. |
| Favorable intermediate risk | Selected Grade Group 2 with PSA <10, or Grade Group 1 with PSA 10–20, while still clinically localized. | Selected AS for very favorable low-volume disease or definitive surgery/radiation. |
| Unfavorable intermediate risk | Grade Group 3, or selected Grade Group 2 with less favorable PSA/stage features. | Definitive treatment generally recommended when life expectancy justifies it. |
| High risk | Grade Group 4–5 OR PSA >20 ng/mL, with staging refinements. | Higher risk of recurrence/metastasis; multimodal treatment often needed. |
| Locally advanced | cT3–4 and/or clinically positive regional nodes, regardless of Grade Group/PSA. | Usually multimodal local + systemic treatment. |
Why Can Two Men With the Same Gleason Score Need Different Treatment?
Consider two men who both have Gleason 3+4=7 / Grade Group 2.
One might have:
- PSA 5 ng/mL;
- one small positive biopsy core;
- 5% pattern 4;
- small MRI lesion;
- no cribriform pattern.
The other might have:
- PSA 17 ng/mL;
- many positive cores;
- extensive pattern 4;
- a larger MRI lesion; and
- other adverse pathology.
Their Gleason score is nominally the same, but their recurrence risk and treatment recommendations may be very different.
What Is Cribriform or Intraductal Prostate Cancer?
Modern pathology reports increasingly identify cribriform growth and intraductal carcinoma of the prostate (IDC-P).
These architectural findings are clinically important because they are associated with more aggressive disease.
EAU notes that modern risk models increasingly incorporate cribriform/intraductal status because it can improve prediction beyond traditional Grade Group alone.
Patients with these findings should not interpret a seemingly favorable Gleason score without discussing the complete pathology report.
What Does “Percentage Pattern 4” Mean?
For Grade Group 2 and some Grade Group 3 cancers, pathologists may report how much of the cancer is Gleason pattern 4.
For example:
Gleason 3+4=7 with 5% pattern 4
is generally biologically different from:
Gleason 3+4=7 with 40% pattern 4.
The percentage of pattern 4 can help determine whether a Grade Group 2 cancer is favorable enough for selected surveillance or should be treated definitively.
Can the Gleason Score Change After Surgery?
Yes.
A biopsy samples only portions of the prostate.
After radical prostatectomy, the pathologist can examine the entire removed gland. The final surgical Grade Group can therefore be:
- the same;
- upgraded to a higher grade; or
- occasionally downgraded.
This does not mean the cancer suddenly changed because of surgery. It usually means the larger surgical specimen provided a more complete picture than the biopsy.
Can MRI Determine the Gleason Score?
No.
MRI can identify suspicious areas and estimate the likelihood of clinically significant cancer, but Gleason/Grade Group requires microscopic examination of tissue.
MRI-targeted biopsy can improve sampling of suspicious lesions, but the pathologist—not the MRI scanner—assigns the grade.
Can PSA Tell You the Gleason Score?
No.
PSA and grade are related to risk but measure different things.
A man can have:
- high PSA with lower-grade cancer;
- low PSA with aggressive high-grade cancer; or
- high PSA because of BPH or inflammation rather than cancer.
Read our PSA test guide.
Does a Gleason Score Predict Life Expectancy?
Not by itself.
The old page assigned fixed life-expectancy estimates to low-, intermediate- and high-risk Gleason groups. That is not medically reliable.
Individual prognosis depends on:
- Grade Group;
- TNM stage;
- PSA;
- biopsy burden;
- PSA kinetics in recurrence;
- PSMA PET or other staging findings;
- genomic alterations in selected patients;
- response to treatment;
- age and competing health conditions; and
- availability of modern salvage/systemic treatments.
A localized Grade Group 4 cancer treated aggressively can have a very different outlook from metastatic Grade Group 4 disease.
How Does Grade Group Affect Treatment?
Grade Group 1
For many men with low-risk localized Grade Group 1 disease and sufficient life expectancy, current guidelines favor:
active surveillance rather than immediate surgery or radiation.
Watchful waiting is different: it is generally used when life expectancy is limited or curative treatment would not provide meaningful benefit.
Selected Grade Group 2
Options can include:
- carefully selected active surveillance for very favorable low-volume disease;
- radical prostatectomy;
- external-beam radiation;
- brachytherapy; or
- other guideline-supported definitive approaches.
Grade Group 3
Active surveillance is generally inappropriate.
When disease is localized and the patient is fit for curative treatment, options commonly include:
- radical prostatectomy; or
- radiotherapy, often with short-term ADT according to the complete intermediate-risk profile.
Grade Groups 4–5
These are high-grade cancers and often require a multimodal strategy.
For high-risk localized disease, options can include:
- radical prostatectomy in selected patients as part of potential multimodal treatment; or
- modern radiotherapy + long-term ADT, generally 2–3 years.
Selected very high-risk or node-positive patients may also receive additional systemic treatment.
What If the Cancer Is Metastatic?
Metastasis is designated M1—the number one—not “MI.”
Once prostate cancer is metastatic, treatment is determined primarily by the metastatic disease state rather than by Gleason score alone.
For metastatic hormone-sensitive disease, modern treatment usually uses:
- ADT plus an androgen-receptor pathway inhibitor; and
- selected triplet treatment including docetaxel in appropriate fit patients.
For metastatic castration-resistant disease, additional options can include:
- taxane chemotherapy;
- PARP-based treatment for selected genomic alterations;
- PSMA radioligand therapy;
- radium-223 in selected bone-predominant disease;
- sipuleucel-T in selected patients; and
- other biomarker-directed therapy.
Does High Grade Mean You Need Orchiectomy?
No.
The legacy page suggested total androgen deprivation, sometimes with surgical castration, as the principal treatment for high-grade disease.
That is obsolete as a general rule.
For high-risk but non-metastatic prostate cancer, treatment often combines definitive local therapy with systemic treatment—not ADT alone.
Orchiectomy remains a valid permanent method of testosterone suppression when long-term ADT is required, but most men today use medical ADT with GnRH agonists or antagonists.
What Should You Look for on a Modern Prostate Biopsy Report?
Useful pathology information includes:
- Gleason score;
- ISUP Grade Group;
- number of biopsy cores containing cancer;
- percentage of each core involved;
- percentage pattern 4 where relevant;
- cribriform architecture;
- intraductal carcinoma;
- perineural invasion when reported;
- histologic subtype; and
- targeted versus systematic biopsy findings.
These findings should be interpreted alongside MRI, PSA and clinical stage.
Questions to Ask After Receiving a Gleason Score
- What is my exact Gleason score—3+4 or 4+3, not just “7”?
- What is my ISUP Grade Group?
- How much pattern 4 is present?
- Is cribriform growth or intraductal carcinoma present?
- How many biopsy cores contain cancer?
- What percentage of each core is involved?
- What is my PSA in ng/mL?
- What is my clinical stage?
- What did MRI show?
- Do I need PSMA PET or other staging tests?
- What is my complete risk group?
- Am I a candidate for active surveillance?
- If treatment is advised, why is surgery or radiation preferred in my case?
When a patient tells me, “My Gleason score is 7,” my next question would be: 3+4 or 4+3? Those two cancers both total seven, but they do not carry the same risk. This is exactly why the modern Grade Group system is so useful.
I would also reassure a patient with Gleason 3+3=6 that six is the lowest score routinely assigned to prostate cancer on a contemporary biopsy. It does not mean the cancer is “six out of ten severe.”
At the same time, I would never choose treatment from the grade alone. The pathology must be combined with PSA, clinical stage, MRI, biopsy volume, adverse histology and—when appropriate—PSMA PET or genomic information.
Finally, grade and stage should never be confused. A high-grade cancer is biologically more aggressive, but only proper staging tells us whether it remains inside the prostate, involves regional structures or has metastasized.
Dr. Albana Greca, MD, MMedSc
Family Physician / General Practitioner
Founder & Lead Medical Author, Prostate Treatment Options
Medical References
European Association of Urology. Prostate Cancer Guidelines, 2026: Gleason/ISUP grading, Grade Groups, EAU risk classification and staging.
European Association of Urology. Prostate Cancer Treatment Guidelines, 2026: active surveillance, intermediate-risk and high-risk treatment recommendations.
National Cancer Institute. Prostate Cancer Treatment PDQ: Gleason score, Grade Groups and prostate-cancer staging.
American Urological Association / ASTRO. Clinically Localized Prostate Cancer Guideline: risk stratification and management principles.
Last evidence update: September 2026.
Medical information notice: Gleason score and Grade Group are only part of prostate-cancer risk assessment. Treatment decisions require integration with PSA, TNM stage, imaging, biopsy extent, pathology features, health and patient preferences.