What is a Gleason Score?

After the biopsy of your prostate cancer, your doctor will explain the results to you using something called a Gleason Score. This grading system was devised in the 1960’s by a pathologist named Donald Gleason who realized that cancerous cells fall into 5 distinct patterns as they change from normal cells to tumor cells. The cells are scored on a scale of 1 to 5. Those cells closest to 1 are considered to be “Low-grade” tumor cells and tend to look similar to normal cells. Cells closest to 5 are considered “High-grade” and have mutated so much that they barely resemble normal cells.

How is Gleason Score derived?

The pathologist looking at the biopsy sample will assign one Gleason grade to the most predominant pattern in your biopsy and a second Gleason grade to the second most predominant pattern. For example: 3 +4. The two grades will then be added together to determine your Gleason score (between 2 and 10).

What Does it Mean?

Generally speaking, cancers with lower Gleason scores (2 – 4) tend to be less aggressive, while cancers with higher Gleason scores (7 – 10) tend to be more aggressive.

It’s also important to know whether any Gleason 5 is present, even in just a small amount, and most pathologists will report this. Having any Gleason 5 in your biopsy or prostate puts you at a higher risk of recurrence.

How Will this Affect my Treatment Plan?

The lower your Gleason Score, the more likely it is that your doctor will recommend Active Surveillance. However, your doctor will take your Gleason Score as well as many other factors into consideration when determining a treatment plan.

Terms to know from this article:


The removal of cells or tissues for examination under a microscope. When only a sample of tissue is removed, the procedure is called an incisional biopsy or core biopsy. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. When a sample of tissue or fluid is removed with a needle, the procedure is called a needle biopsy or fine-needle aspiration.


Gleason Score (GS) - Gleason Grade: A system of grading prostate cancer cells based on how they look under a microscope. Gleason scores range from 2 to 10 and indicate how likely it is that a tumor will spread. A low Gleason score means the cancer cells are similar to normal prostate cells and are less likely to spread; a high Gleason score means the cancer cells are very different from normal and are more likely to spread.


A system for classifying cancer cells in terms of how abnormal they appear when examined under a microscope. The objective of a grading system is to provide information about the probable growth rate of the tumor and its tendency to spread. The systems used to grade tumors vary with each type of cancer. Grading plays a role in treatment decisions.


A doctor who identifies diseases by studying cells and tissues under a microscope.


A mass of excess tissue that results from abnormal cell division. Tumors perform no useful body function. They may be benign (not cancerous) or malignant (cancerous).


The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer.

Active Surveillance

Active surveillance is an option offered to patients with very low-risk prostate cancer (low grade, low stage, localized disease). Patients are monitored carefully over time for signs of disease progression. A PSA blood test and digital rectal exam (DRE) and prostate biopsy are performed at physician-specified intervals. Signs of disease progression will trigger immediate active treatment.