If you are diagnosed with prostate cancer, there are two critical things that your doctor is going to want to try to estimate as soon as possible. These are the clinical stage of your disease and the grade of your disease.
The Clinical Stage
The clinical stage is an estimate of how far your cancer has progressed. So, for example, if the doctor believes your cancer is still entirely confined to the prostate, and he only found the disease because of a slightly elevated PSA test and a small amount of cancer in a couple of biopsy cores, then he is likely to decide you have what would be called clinical stage T1c or A2 disease (depending on the staging system he was using).
The two most commonly used prostate cancer staging systems are the international TNM staging system and the older Jewett-Whitmore staging system (which uses the ABCD letter code system). A slightly different system (properly known as the AJCC stage grouping system) combines the clinical stage with the histopathologic grade (which is what we will talk about next).
The Pathological Grade
The pathological grade of your cancer is normally given (at least in North America) by the use of a system called Gleason grading. The pathological grade is a way to estimate the “aggressiveness” of your cancer, or how fast it may be growing. The higher the Gleason score (which can be anything from 2 to 10), the more aggressive your cancer is. Most patients today have Gleason scores of between 5 and 7.
Outside North America it is relatively common to find the use of the World Health Organization grading system.