Gleason Score and Grade Groups

Diagnosing prostate cancer starts with a biopsy. When abnormal cells are found in the prostate tissue samples removed during the biopsy, a pathologist will assign a score to the two most predominant cell patterns to create a Gleason score. Based on the Gleason score, the prostate cancer’s grade is determined. This will direct the next steps in the treatment process. 

What is a Gleason Score? 

The Gleason score is a grading system for prostate cancer, named after the doctor who established this scoring system. As cancer cells grow and divide, they look different from healthy cells. The more advanced the cancer, the less the cells look like healthy cells. 

The pathologist reviewing the tissue samples will assign a number between 1 and 5 to the first and second most common patterns. A one means the cells look healthy, while a score of five means the cells are highly different from healthy cells. The two numbers are then added together to establish the patient's Gleason score. This information is included in the pathology report.

Understanding the Gleason Score

The Gleason score determines the aggressiveness of prostate cancer and the likelihood of it spreading. Below is a more detailed explanation of what your Gleason score means. Note that any score less than a six is not considered cancer.

  • Gleason score of 6: Indicates that the cancer is likely to grow slowly, means it’s low-grade cancer. The cancerous cells look closer to healthy cells. Patients with this score typically have the best treatment outcomes. The most common approach for patients with a Gleason score of 6 is watchful waiting, also called active surveillence. No treatments are necessary right away since the cancer is growing slowly.
  • Gleason score of 7: The cancerous cells look less like healthy cells. The patient's next steps depend on which pattern is more prevalent. If the first score assigned to the most predominant cell pattern is a 3, and the second most predominant cell pattern is a 4, the Gleason score is 3+4=7. Treatment may not be necessary yet.

    However, if the Gleason score is 4+3=7, the most predominant cell pattern is more aggressive than if the three came first. Treatment may need to begin, or the waiting period may be shorter for these patients.
  • Gleason Score of 8-10: Indicates that the cancer is aggressive and likely to grow rapidly and spread to other parts of the body if it hasn’t already. These cells look very different from healthy cells. While the prognosis for those with a Gleason score of 8 is better than those with a score of 10, immediate treatment is critical. 

Prostate Cancer Grade Groups

The grade group system is a newer, more straightforward system than the Gleason score. Under this system, cancer cells are classified into grade groups 1 through 5. A grade group of 1 means the cancerous cells look almost normal and are growing slowly, if at all. A grade group of 5 means the cells look very abnormal and are growing quickly.

Here is how grade groups correlate with the Gleason score: 


  • Grade 1: Gleason score of 6 or less


  • Grade 2: Gleason score of 3+4=7 
  • Grade 3: Gleason score of 4+3=7


  • Grade 4: Gleason score of 8 
  • Grade 5: Gleason score of 9 to 10 

The grade group system can be more precise than the Gleason score. For example, Grades 2 and 3 have the same Gleason score, but the aggressiveness of the cancer is different. Using the Gleason score and grades together can help the urologist make their best recommendation on what should happen next. 

If Prostate Cancer is Detected, What’s Next?

The Gleason score, along with the grade of cancer, will help the doctor assess how quickly the cancer is growing. For intermediate or high-grade cancers, additional tests are needed to see if the cancer has spread outside the prostate. Treatment may begin quickly, and an oncologist should lead it. They will finalize the stage of cancer and determine the timing of each treatment, including surgery, if necessary.

Related reading: Understanding The Differences Between Surgery and Radiation to Treat Prostate Cancer

Less aggressive cancers are likely to follow the active surveillance procedure of follow-up PSA blood tests and digital exams every six months. If the PSA numbers continue to go up, a repeated biopsy may also be needed. These patients have some time to review treatment options and discuss them with one or more cancer specialists in addition to the urologist. 

Prostate Cancer Treatment Options in Albany

Remember that there are more options than surgery if prostate cancer is found. For those whose cancer is found at a later stage, surgery is more likely. Talk to an oncologist about what’s best for you. They will work with your urologist to create a treatment plan that can be started when the time is right.