What is the Gleason Score?

Donald Gleason developed the Gleason score in the 60s, based on the following observation: Tissue in the prostate changes in predictable patterns as it changes from a normal to a cancerous state.

The International Society of Urological Pathology (ISUP) amended the Gleason score in 2005, and it now includes patterns 6-10. It is a major prognostic factor and is used whenever a positive sample is obtained from a prostate biopsy. It provides a valuable indication of the aggression and progression of diseased prostate tissue.

The Gleason score uses three grades to classify prostate tissue: 3, 4, and 5. Whenever a sample is taken from the prostate, the Gleason score is calculated as the sum of the most widespread highest grade + the second highest grade.

Here’s a detailed example:

Most widespread highest grade: 4

Second highest grade: 5

Gleason score: 9 (4+5)

Please note: The Gleason score cannot be used with patients who have already received a treatment of hormone therapy, external radiotherapy or brachytherapy.

The importance of the Gleason Score

A prostate biopsy is the only medical procedure that can confirm a prostate cancer diagnosis. Tissue samples obtained from a prostate biopsy taken using ultrasound guidance are sent to the lab and analysed by an anatomical pathologist who then issues a report.

The Gleason score is a key piece of data that the urologist can use to make an accurate diagnosis of the cancer’s progression, and decide which treatment strategy to use.

A number of samples may be taken in a single prostate biopsy intervention. When the cancer is spread throughout the prostate, they are known as “systemic biopsies”; when they are taken from a suspect area identified through medical imaging, like MRI, they are known as “targeted biopsies”.

However, it is important to note that with systemic biopsies, a low or null Gleason score does not mean that there is no aggressive cancer. MRI-Ultrasound (MRI-Echo or TRUS-MR) prostate fusion biopsies can target suspect areas and ensure an accurate assessment of how aggressive the potential cancer is.

What does the Gleason Score mean?

Below you will find a detailed explanation for the different Gleason scores and what they mean.

Gleason Score of 6

The lowest possible score for prostate cancer discovered in a biopsy. Level 6 cancers are not aggressive and progress slowly. This Gleason score is always the sum of cells representing grade 3 (3+3 = 6).

  • Cancer risk: Low

Gleason Score of 7

According to Gleason’s methodology, level 7 cancers may not be aggressive, but may have the potential to be. Indeed, two cases can produce this score: Gleason score 3+4 or 4+3. This difference may seem trifling, but it represents a significant difference between two grade 7 cancers.

Grades 3 + 4 = 7

  • Definition: Not very aggressive cancer
  • Cancer risk: Medium favourable

Grades 4 + 3 = 7

  • Definition: Potentially aggressive cancer with rapid progression
  • Cancer risk: Medium unfavourable

Gleason Scores of 8, 9 and 10

Cancers with a Gleason score of 8 or above are deemed to be aggressive, with a tendency to progress quickly. The closer to the maximum score of 10, the more virulent the cancer will be.

  • Risk: High

New ISUP Classification

See the following publication:

The 2014 International Society of Urological Pathology (ISUP) Consensus Conference on Gleason Grading of Prostatic Carcinoma: Definition of Grading Patterns and Proposal for a New Grading System. 

In November 2014, the International Society of Urological Pathology (ISUP) convened to ratify an update to the system used to classify prostate cancer.

The 65 experts and 17 clinicians who attended the conference went on to approve a new classification method, based on data from John Hopkins Hospital (Baltimore, Maryland, USA).

Clearer and easier for patients to understand, this new method is known as “ISUP Grade Groups” and is made up of levels 1–5. It is still based on the Gleason score, but corrects its main defects.

Risk Group ISUP Grade Group Gleason Score
Low Grade Group 1 Gleason Score ≤ 6
Intermediate Favorable Grade Group 2 Gleason Score 7 (3+4)
Intermediate Unfavorable Grade Group 3 Gleason Score 7 (3+4)
High Grade Group 4 Gleason Score 8
High Grade Group 5 Gleason Score 9-10

 

KOELIS™ technology for Prostate Cancer diagnosis

For over a decade KOELIS has assisted urologists and radiologists from around the world in their routine clinical practice providing the latest technology for prostate cancer care. In order to bring personalized answers to every patient in the respect of their quality of life, we’ve developed KOELIS Trinity™ prostate fusion biopsy system. This system allows physicians to perform precise and targeted transperineal or transrectal MRI/US fusion guided biopsies under local or general anesthesia.

“Quality management in patient diagnosis”

It is equipped with the exclusive Organ-Based Tracking™ (OBT) technology which guarantees the accuracy of the biopsy. Without changing the usual clinical practices, this technique leads to increase control from biopsy localizations specifically for each patient and, consequently, to higher detection rate and stronger basis for further prostate cancer management.

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