How is Prostate Cancer Graded and Staged?
Grading (with the Gleason Score) and staging defines the progress of cancer and whether it has spread:
When prostate cancer cells are found in tissue from the core biopsies, the pathologist "grades" it. The grade is a measure of how quickly the cells are likely to grow and spread (how aggressive it is).
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. Gleason scores of 8 and above are treated as high-risk cancers.
If you are diagnosed with prostate cancer, ask about your Gleason score and how it impacts your treatment decisions.
Tumor stage is also measured. Staging describes where the cancer is within the prostate, how extensive it is, and if it has spread to other parts of the body. One can have low stage cancer that is very high risk. Staging the cancer is done by DRE and special imaging studies.
The system used for tumor staging is the TNM system. TNM stands for Tumor, Nodes and Metastasis. The "T" stage is found by DRE and other imaging tests such as an ultrasound, CT scan, MRI or bone scan. The imaging tests show if and where the cancer has spread, for example: to lymph nodes or bone.
These staging imaging tests are generally done for men with a Gleason grade of 7 or higher and a PSA higher than 10. Sometimes follow-up images are needed to evaluate changes seen on the bone scan.
Not all men need imaging tests. Your doctor may recommend imaging exams based on results from other tests.
Prostate cancer may spread from the prostate into other tissues. It may spread to the nearby seminal vesicles, the bladder, or further to the lymph nodes and the bones. Rarely, it spreads to the lungs and or other organs.
What Are The Survival Rates For Prostate Cancer?
Many men with prostate cancer will not die from it; they will die from other causes. For men who are diagnosed, it is better if it is caught early.
Survival rates for men with prostate cancer have increased over the years, thanks to better screening and treatment options. Today, 99% of men with prostate cancer will live for at least 5 years after diagnosis. Many men having treatment are cured. Most prostate cancer is slow-growing and takes many years to progress. One out of three men will survive after five years, even if the cancer has spread to other parts of the body.
Updated August 2018