Prostate Cancer Gleason Score
Content contributed by R. Alex Hsi, M.D.
Peninsula Cancer Center
Prostate Cancer Diagnosis is Confirmed with a Biopsy
Prostate Cancer Gleason Score: The biopsy can give important indications as to how extensive the cancer is within the prostate by the number of cores that are positive for cancer. The pathologist will also look for perineural invasion, (cancer invading small nerves within the prostate), which can be an indication of how likely the cancer is to spread outside of the gland.
Prostate Cancer Gleason Score is Set by Inspection of Prostate Cancer Cells
Based on screening tests, a biopsy may be recommended and performed as described using transrectal ultrasound guidance. A pathologist will then examine the tissue samples under a microscope to determine whether or not the prostate contains cancerous tissue. When cancer is discovered, it is classified by a Prostate Cancer Gleason Score. A Prostate Cancer Gleason Score or Grade helps to determine how aggressively the prostate cancer is likely to behave both in how quickly it grows and how likely it is to spread outside of the gland.
- The Prostate Cancer Gleason Score score ranges from 2 to 10.
- To determine the Gleason score, the pathologist uses a microscope to look at the patterns of cells in the prostate tissue.
- The most common cell pattern is given a grade of 1 (most like normal cells) to 5 (most abnormal).
- If there is a second most common cell pattern, the pathologist gives it a grade of 1 to 5.
- The pathologist adds the two most common grades together to make the Gleason score. If only one pattern is seen, the pathologist counts it twice, e.g. 5 + 5 = 10.
- A high Gleason score (such as 10) means a high-grade prostate tumor.
- High-grade tumors are more likely than low-grade tumors to grow quickly and spread.
How Does the Pathologist Grade the Prostate Cancer Gleason Score?
Description of Biopsy Results
Gleason Score 1
The cancerous tissue looks very much like normal prostate cells.
Gleason Score 2-4
Some cells do look like normal prostate cells, other cells do not.
Patterns of cells in these grades vary.
Gleason Score 5
The cells appear abnormal and do not look like normal prostate cells.
Abnormal cells appear to be scattered haphazardly throughout the prostate.