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Prostate Cancer: The Gleason Score Explained

How aggressive is my prostate cancer? Is it growing slowly or quickly?

If you’ve been diagnosed with prostate cancer—and this year alone nearly 165,000 men nationwide will be—these may be among the first questions you’ll ask your doctor. And the answers will most likely take into account something called a Gleason score.

The Gleason score is a grading system used by urologists to assess a prostate cancer’s aggressiveness based on how cells from the tumor look under a microscope. Less-aggressive tumors are more likely to resemble healthy prostate tissue. More-aggressive tumors look less like normal tissue.

The higher the Gleason score, the more aggressive your cancer is likely to be—and the greater the chance that it will spread. Doctors use the Gleason score to help choose appropriate treatments.

What the numbers mean

The pathologist who examines the cells—taken during your biopsy—will look at their patterning in the samples. Each area is graded on a scale of 1 to 5, and the two numbers are added together to get the Gleason score.

If a Gleason score is written in your pathology report as 3+4=7, this means most of your tumor is grade 3 and less of it is grade 4. These numbers are then added together for a total Gleason score of 7.

Grades 1 and 2 are not usually used to describe cancer —these grades are for tissue that almost looks normal and isn't considered cancerous. The lowest possible Gleason score of a cancer found in a prostate biopsy is 6—cancer with the least risk of spreading quickly. The highest score is 10—cancer with the most risk of being aggressive.

Because a scoring system that starts with the number 6 can be confusing, recently the Gleason Grade Grouping were introduced. This group number is based on the numbers used to create a sample’s Gleason score, but start with 1 instead of 6 and  range from 1 (most favorable prognosis) to 5 (least favorable prognosis).

Gleason Grade Groups:

Group 1: A Gleason score of 6 (3+3=6) or less

Group 2: Gleason score of 7 (3+4=7)

Group 3: Gleason score of 7 (4+3=7)

Group 4: Gleason score of 8 (4+4=8)

Group 5: Gleason score of 9-10 (4+5=9, 5+4=9, 5+5=10)

What are my treatment options?

As important as a Gleason score is, it is only one indication of whether prostate cancer is likely to spread. Findings on rectal exams, prostate-specific antigen (PSA) blood tests, and imaging tests—and whether the cancer has already spread outside the prostate—are also important.

For men with low-risk prostate cancer, determined by a low Gleason score—your doctor may not recommend any treatment at all, but instead suggest carefully monitoring the cancer with testing, physical exams, biopsies, or imaging. This approach is called  active surveillance.

One important thing to keep in mind is to seek treatment at a center with expertise in treating prostate cancer. The Gleason score combined with other factors is an incredibly valuable tool, but only in the hands of experienced and knowledgeable  physicians who know how to put into the context of your particular situation.

Whatever your Gleason score, our experienced prostate cancer team at Fox Chase will work with you to determine the best plan for you.

Read more about prostate cancer treatment options at Fox Chase.

For more information on prostate cancer, download our Prostate Cancer Guide