When your doctor diagnoses you with advanced prostate cancer, they'll use several tests to plan your treatment. A biopsy (when the doctor takes a small piece of tissue to test in a lab) and a Gleason score can check for cancer and help see how fast-growing your cancer is.
What Is the Gleason Grading System?
Your Gleason score isn't a separate test. It's a number based on the results of your biopsy. You usually get it when you're first diagnosed with prostate cancer.
It's the sum of two grades on your lab report. They focus on the most common and second-most common cancer cell patterns in a biopsy.
The doctor uses the numbers 1 to 5 to grade the most common (primary) and second most common (secondary) patterns of cells found in a tissue sample:
- Grade 1. The cells looks very much like normal prostate cells.
- Grades 2-4. Cells that score lower look closest to normal and represent a less aggressive cancer. Those that score higher look the furthest from normal and will probably grow faster.
- Grade 5. Most cells look very different from normal.
The two grades added together are your score. It can range from 2 to 10, but most cancers will score 6 or more. A higher score (8 to 10) means the cancer is more likely to grow and spread.
Transrectal Ultrasound-Guided Biopsy
For this procedure, the doctor takes a biopsy from your prostate. The tissue goes to a lab for testing. They can tell if you have cancer and, if so, how fast it might grow.
The biopsy takes about 10 minutes. You can get it done in your urologist's office. You will be awake for it. It usually doesn’t hurt much.
In the most common type of biopsy, your doctor places a device called an ultrasound probe in your rectum. It's about the width of a finger. It gives off sound waves that bounce off your prostate and create a black and white image on a video screen. A newer method uses an MRI scan to biopsy the prostate.
With the picture of your prostate as a guide, your doctor inserts a thin, spring-loaded, hollow needle through the wall of your rectum and into your prostate gland. As your doctor removes the needle, they take out a tiny bit of prostate tissue.
Because prostate cancer is rarely only in one area of the prostate, your doctor will take an average of 12 pieces of tissue, or samples, from different parts of your prostate. They may take more samples if they think they need to.
It's possible to have different types of cancer in the same prostate. Your doctor will get each tissue sample checked by a lab. The lab report will tell your doctor if cancer is present in each sample, how much of the tissue sample contains cancer, and your Gleason score.