Gleason grading system
The Gleason grading system is used to help evaluate the prognosis of men with prostate cancer using samples from a prostate biopsy. Together with other parameters, it is incorporated into a strategy of prostate cancer staging which predicts prognosis and helps guide therapy. A Gleason score is given to prostate cancer based upon its microscopic appearance. Cancers with a higher Gleason score are more aggressive and have a worse prognosis. Pathological scores range from 2 to 10, with higher numbers indicating greater risks and higher mortality. The system is widely accepted and used for clinical decision making even as it is recognised that certain biomarkers, like ACP1 expression, might yield higher predictive value for future disease course.
| Gleason grading system | |
|---|---|
Gleason grade — Lower grades are associated with small, closely packed glands. Cells spread out and lose glandular architecture as grade increases. Gleason score is calculated from grade as described in the text. |
The histopathologic diagnosis of prostate cancer has implications for the possibility and methodology of Gleason scoring. For example, it is not recommended in signet-ring adenocarcinoma or urothelial carcinoma of the prostate, and the scoring should discount the foamy cytoplasms seen in foamy gland carcinoma.
A total score is calculated based on how cells look under a microscope, with the first half of the score based on the dominant, or most common cell morphology (scored 1 to 5), and the second half based on the non-dominant cell pattern with the highest grade (scored 1 to 5). These two numbers are then combined to produce a total score for the cancer.