Gleason grading system
Prostate cancer - Gleason; Adenocarcinoma prostate - Gleason; Gleason grade; Gleason score; Gleason group; Prostate cancer - 5 grade group
Prostate cancer is diagnosed after a biopsy. One or more tissue samples are taken from the prostate and examined under the microscope.
The Gleason grading system refers to how abnormal your prostate cancer cells look and how likely the cancer is to advance and spread. A lower Gleason grade means that the cancer is slower growing and is less aggressive.
As men get older, they have a lot of new worries to deal with, from hair loss, weight gain, perhaps even erectile dysfunction. In addition, cancer is one of the biggest concerns that older men face, especially prostate cancer, which is the leading cause of cancer death in men over 75. Younger men may not be very familiar with their prostate, the walnut-shaped gland that wraps around the urethra, the tube that carries urine out of the body. But as they get older, the prostate can start to cause problems. Men over the age of 60 are at increased risk for prostate cancer, especially if they're of African descent, they have a father or brother with the disease, or they eat a lot of burgers and processed meats in their daily diet. It can be hard to pinpoint prostate cancer symptoms, because they usually start late in the disease and they can mimic symptoms of a benign, enlarged prostate, which is also more common in older men. Symptoms like a slow urine stream, dribbling, blood in the urine, or straining while urinating can be signs of either condition. An enlarged prostate can also confuse the results of a PSA test, which is used to screen for prostate cancer. So, if your doctor thinks you might have prostate cancer, you may need a biopsy, which is a procedure that removes a small piece of prostate tissue and sends it to the lab to check for cancer. Then a scoring system called the Gleason grade is used to tell how fast your cancer might spread. Your Gleason grade will help decide what treatment you get. Early-stage prostate cancers that haven't spread are often removed with surgery, and then treated with radiation therapy to kill any remaining cancer cells. Prostate cancer surgery may affect your ability to have sex and control urine, so talk about these issues with your doctor before you have the procedure. Because prostate cancer tends to grow very slowly, your doctor may want to just monitor you with PSA tests and biopsies, and avoid treatment unless the cancer starts to spread. Prostate cancer that has spread is usually treated with surgery, chemotherapy, or hormone therapy. If your doctor discovers prostate cancer in its early stages, before it spreads, it's pretty easy to treat, and even cure. Treatments can also slow down prostate cancer that's spread, and extend your survival. Before you have to deal with a prostate cancer diagnosis, ask your doctor for ways to prevent and screen for the disease. Eating a healthy, low-fat diet that's high in healthy omega-3 fatty acids might help lower your risk. There are also drugs called finasteride and dutasteride that are used in some men to prevent prostate cancer. Talk with your doctor about the pros and cons of these drugs, as well as the possible benefits and risks of having your PSA levels tested.
Gleason Score
The first step in determining the Gleason grade is to determine the Gleason score.
- When looking at cells under the microscope, the doctor (pathologist) assigns a number (or grade) to the prostate cancer cells from 1 to 5.
- This grade is based on how abnormal the cells appear. Grade 1 means that the cells look almost like normal prostate cells. Grade 5 means that the cells look very different from normal prostate cells.
- Most prostate cancers contain cells that are different grades. So the two most common grades are used.
- The Gleason score is determined by adding the two most common grades. For example, the most common grade of the cells in a tissue sample may be grade 3 cells, followed by grade 4 cells. The Gleason score for this sample would be 7.
Higher numbers indicate a faster growing cancer that is more likely to spread.
Currently the lowest score assigned to a tumor is grade 3. Grades below 3 show normal to near normal cells. Most cancers have a Gleason score (the sum of the two most common grades) of 6 (Gleason scores of 3+3) or 7 (Gleason scores of 3+4 or 4+3).
Gleason Grading System
Sometimes, it can be hard to predict how well people will do based just on their Gleason scores alone.
- For example, your tumor may be assigned a Gleason score of 7 if the two most common grades were 3 and 4. The 7 may come either from adding 3 + 4 or from adding 4 + 3.
- Overall, someone with a Gleason score of 7 that comes from adding 3 + 4 is felt to have a less aggressive cancer than someone with a Gleason score of 7 that comes from adding 4 + 3. That is because the person with a 4 + 3 =7 grade has more grade 4 cells than grade 3 cells. Grade 4 cells are more abnormal and more likely to spread than grade 3 cells.
A 5 Grade Group System was created to have a better way to describe how a cancer will behave and respond to treatment.
- Grade group 1: Gleason score 6 or lower (low-grade cancer)
- Grade group 2: Gleason score 3 + 4 = 7 (medium-grade cancer)
- Grade group 3: Gleason score 4 + 3 = 7 (medium-grade cancer)
- Grade group 4: Gleason score 8 (high-grade cancer)
- Grade group 5: Gleason score 9 to 10 (high-grade cancer)
A lower group indicates a better chance for successful treatment than a higher group. A higher group means that more of the cancer cells look different from normal cells. A higher group also means that it is more likely that the tumor will spread aggressively.
Grading helps you and your health care provider determine your treatment options, along with:
- Stage of the cancer, which shows how much the cancer has spread
- PSA test result
- Your overall health
- Your desire to have surgery, radiation, or hormone medicines, or no treatment at all
References
Bostwick DG, Cheng L. Neoplasms of the prostate. In: Cheng L, MacLennan GT, Bostwick DG, eds. Urologic Surgical Pathology. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 9.
Epstein JI. Pathology of prostatic neoplasia. In: Partin AW, Dmochowski RR, Kavoussi LR, Peters CA, eds. Campbell-Walsh-Wein Urology. 12th ed. Philadelphia, PA: Elsevier; 2021:chap 151.
National Cancer Institute website. Prostate cancer treatment (PDQ) health professional version.
Version Info
Last reviewed on: 5/17/2024
Reviewed by: Sovrin M. Shah, MD, Associate Professor, Department of Urology, The Icahn School of Medicine at Mount Sinai, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
