If the biopsy finds cancer, the pathologist gives it a grade. The most common grading system is called the Gleason grading system. With this system, each tissue piece is given a grade between three (3) and five (5). In the past, we assigned scores of one (1) and two (2). A grade of less than three (3) means the tissue is close to normal. A grade of three (3) suggests a slow growing tumor. A high grade of five (5) indicates a highly aggressive, high-risk form of prostate cancer.
The Gleason system then develops a "score" by combing the two most common grades found in biopsy samples. For example, a score of grades 3 + 3=6 suggests a slow growing cancer. The highest score of grades 5+5=10 means that cancer is present and extremely aggressive.
The Gleason score will help your doctor understand if the cancer is as a low-, intermediate- or high-risk disease. Generally, Gleason scores of 6 are treated as low risk cancers. Gleason scores of around 7 are treated as intermediate/mid-level cancers. There are two types of these scores. A 4+3 tumor is more aggressive than a 3+4 tumor. That's because more of the higher aggressive grade tumor was found. Gleason scores of 8 and above are treated as high-risk cancers. Gleason 8, 9 and 10 tumors are the most aggressive. Some of these high-risk tumors may have already spread by the time they are found. Talk to your health care provider about your Gleason score.
Tumor stage shows the size and spread of the cancer. Cancer in only a small part of the prostate is more treatable than cancer that has spread all through it. Tumors found only in the prostate are more successfully treated than those that have metastasized (spread) outside the prostate. Tumors that have spread to places far from the prostate like lymph nodes or bone are the most difficult to manage and have the poorest results.
Tumor, Nodes and Metastasis (TNM) is the system used for tumor staging.
Using the "T" part of the system, prostate cancer is staged as:
- T1: Health care provider cannot feel the tumor
- T1a: Cancer present in less than 5% of the tissue removed and low grade (Gleason < 6)
- T1b: Cancer present in more than 5% of the tissue removed or is of a higher grade (Gleason > 6)
- T1c: Cancer found by needle biopsy done because of a high PSA
- T2: Health care provider can feel the tumor with a DRE but the tumor is confined to prostate
- T2a: Cancer found in one half or less of one side (left or right) of the prostate
- T2b: Cancer found in more than half of one side (left or right) of the prostate
- T2c: Cancer found in both sides of the prostate
- T3: Cancer has begun to spread outside the prostate and may involve the seminal vesicles
- T3a: Cancer extends outside the prostate but not to the seminal vesicles
- T3b: Cancer has spread to the seminal vesicles
- T4: Cancer has spread to nearby organs such as the urethral sphincter, rectum, bladder, or pelvis wall
- N0 stage, there is no sign of the cancer moving to the lymph nodes in the area of the prostate.
- M0 stage, there is no sign of tumor metastasis.
- If the cancer is spreading to the lymph node or if the tumor has spread to other parts of the body, the stage is changed. It becomes either N1, for node, and/or M1, for metastasis.
Prostate cancer usually spreads from the prostate into nearby tissues. Then it can spread to the seminal vesicles, lymph nodes, bones, lungs, and other organs. Your doctor may want imaging tests to see how far your cancer has spread. These include a pelvic CT, MRI or a bone scan.
Hope for advanced prostate cancer?
There is no cure for advanced prostate cancer. 29,430 deaths from prostate cancer are predicted in the U.S. this year. But advances in science mean cancer growth can be slowed. Treatment can also reduce cancer-related symptoms so you feel better. New therapies are improving survival and quality of life, especially for men with no cancer-related pain.
Updated August 2018