Gleason Score

There are many types of treatments for prostate cancer. Along with other medications, some men are treated with surgery or radiation. At other times, prostate cancer does not need to be treated. It can be “watched,” or monitored from year to year. The decision for treatment with surgery, radiation or watchful waiting depends on many factors. One is these factors is called a Gleason score. After undergoing a prostate biopsy, a doctor that specializes in looking at tissues on microscope, also known as a pathologist, will give a score to grade the cancer cell from not aggressive to aggressive. This is called a Gleason score. Let’s find out more about the Gleason score and how this number can be used to guide the treatment of prostate cancer.

The Gleason score gives a clue into the “differentiation” of a cancer cell. A discussed previously during our breast cancer series, differentiation refers to how similar in appearance a cancer cells looks when compared to a normal cell. Cancer cells arise from normal cells in our body. More plainly, prostate cancer cells arise from normal prostate cells in the body. When a cell becomes cancerous, it loses respect of boundaries and order. It begins to grow uncontrolled, unchecked and unhindered by the cells and structures around it. It even loses the appearance of a normal functioning cell. A poorly differentiated cancer cell looks completely different than the tissue it came from. In this case, a cancer cell tends to be more aggressive. A well differentiated cancer cell has a similar appearance to the tissue it came from. Well differentiated cancer cells have a better outlook and are easier to treat.

The Gleason score gives a clue to how aggressive a cancer cell can be and helps determine a treatment course for prostate cancer. During a biopsy, many samples, up to 10-12, of tissues are taken from the prostate gland. All of these samples are examined by a pathologist and the two most common patterns are highlighted. These 2 patterns are given a score from 1 to 5 based on their “differentiation.” A score of 1 means the tissue looks exactly like a normal prostate cell. A score of 5 means the tissue looks completely different from a normal prostate cell. With a score of 5, the tissue is poorly differentiated and can be difficult to treat (1).

Therefore, in the case of an aggressive prostate cancer, the Gleason score can have a maximum amount of 10. In other words, when a pathologist looks at all the samples of the prostate taken at the time of biopsy, he or she chooses the two most common patterns. The pathologist would take a closer look at these to patterns and give each pattern score of 5. This will be seen as “Gleason = 5 + 5” on a biopsy report. This cancer would be considered somewhat aggressive. Other the other hand, a Gleason score of 6 or less is favorable news. Of the two most common patterns chosen, a pathologist would give each pattern a score of 3. This will be reported as “Gleason = 3 + 3” on a biopsy report. Interestingly, individual scores of 1 or 2 for a particular pattern are considered fairly normal. Therefore, prostate cancer is generally not diagnosed unless a Gleason score, which again is a combined score of two patterns, is 6 or higher (1).

 The decision for treatment with surgery, radiation or watchful waiting depends on many factors. One is these factors is called a Gleason score. The idea of a Gleason score may be difficult to understand. If there remains any confusion, read though this blog again or listen to our podcast on the Gleason score to gain a better understanding. In all, knowing your Gleason score can help empower you to make an informed decision while deciding on a treatment course for prostate cancer. After underdoing a biopsy, ask your doctor “What is my Gleason score?” This will help put you in the driver’s seat of you own health care. Those with a low Gleason score of 6 or less will tend not to need treatment for prostate cancer. Instead, this disease can be watch from year to year.