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What is a Gleason Score for Prostate Cancer and What Does It Mean?

Topics: Prostate Cancer

November 18, 2019

Gleason Score for Prostate Cancer

The Gleason Score is more than likely one of the first things your doctor will discuss if you have received a prostate cancer diagnosis. That’s because it’s used to explain the stage of prostate cancer you have. Let’s discuss prostate cancer, the purpose of the Gleason Score, how it is calculated, and why it is so important.  

What is Prostate Cancer?

The prostate is a gland found only in males that lies just below the bladder and in front of the rectum. Prostates in younger men are about the size of walnuts but tend to become larger as they age. It serves two main functions in the body. The first is to secrete prostate fluid (one of the components that comprises semen) and the second is to help move the seminal fluid into the urethra during ejaculation with the use of muscles.

Prostate cancer occurs when the cells in the prostate gland begin to grow rapidly and out of control. Usually, it starts out growing slowly and stays within the prostate.

There are 5 types of prostate cancers:

  • Adenocarcinomas
  • Small cell carcinomas 
  • Neuroendocrine tumors
  • Transitional cell carcinomas
  • Sarcomas

Chances are high that when you are diagnosed with prostate cancer, it is adenocarcinoma, which starts in the gland cells. 

The other 4 types of prostate cancers are less common. Like all cancers, prostate cancer is graded to determine how aggressive and rapidly it is growing. No matter the type of cancer, all patients diagnosed are staged. This means assigning a grade that defines how aggressive the cancer is. For staging prostate cancer, the Gleason Score is the method used. 

Related reading: Prostate Cancer: When Should Men Be Screened?

What is the Gleason Score?

The Gleason Score was first developed by Donald Gleason in the 1960s and is the grading method that is used to determine how aggressive a patient's prostate cancer is. In most cases, prostate cancer is made up of cancerous cells with different grades. For this reason, each patient is assigned two different grades. The first grade refers to the most dominant grade of cancer cells and the second-grade refers to the second most common dominant grade of cancer cells found during the biopsy. 

How Does Gleason Scoring Work?

If your doctor suspects you have prostate cancer a biopsy may be used to confirm the diagnosis and gain insight its characteristics.  The two most dominant grades of cancer cells found in the biopsy are each given a score of 1 through 5. 

For instance, a patient may be assigned a 4 and a 3. These two numbers are then added together to determine the Gleason Score which is a range of 2-10. In most cases, oncologists never assign a Gleason Score below 6. If we go back to our example, 4 and 3 would be added together for a sum of 7. This means 7 would the patient's Gleason Score. 

What Do the Different Gleason Scores Mean?

The Gleason Score is based on the aggressiveness of the prostate cancer. The lower the number, the closer to normal the cell tissue, and slower-growing the cancer is likely to be. Anything less than 6 is not considered cancer. 

The Gleason Score is based on the aggressiveness of the prostate cancer.

The higher the number, the more aggressive the cancer and the more likely it is to spread. Let's take a look at what the different scores mean:

  • Low Grade: Gleason Score = 6: This indicates that more than likely the cancer will be slow-growing and not very aggressive. Patients with these scores have the best prognosis.
  • Intermediate Grade: Gleason Score = 7: A score of 7 means that the patient has a 50/50 chance of having aggressive prostate cancer. If the patient received a primary grade of 3 and a secondary grade of 4, more than likely the cancer will grow slowly. However, if those numbers are reversed and the primary grade was 4 and the secondary 3, the cancer may be aggressive.
  • High Grade: Gleason Score = 8-10: A score of 8-10 means the cancer is aggressive and likely to grow and spread at a rapid pace.  

Why is the Gleason Score Important?

According to a study conducted by the University of Geneva, the Gleason score correlates very closely with the clinical behavior of the cancer cells. This makes is a very important indicator of how the cancer will act – slowing growing versus aggressive. 

It tells oncologists a great deal about the characteristics of the prostate cancer although it’s not the only tool used to determine whether you need to move ahead with treatment.  Other factors are used and evaluated as a whole. This can include one more of the following:

  • PSA blood test score 
  • Physical examination findings
  • Imaging test results
  • Whether cancer was found on both sides of the prostate
  • Whether cancer has spread outside the prostate

Arizona's Leader in Prostate Cancer Treatment & Research

Arizona Oncology understands that those facing a prostate cancer diagnosis are warriors. This is why our staff is comprised of compassionate caregivers to help you through every step of the way. When you choose Arizona Oncology, you can rest assured that you are receiving the highest-quality prostate cancer care available from highly experienced clinicians. Contact us today for more information

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