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.