The "G" Rating--Tumor Cell Grading
In addition to the TNM model for rating your prostate cancer, the tumor cells themselves are studied and graded to attempt to determine how aggressive it is (the more aggressive, the more aggressive the treatment should be.)
The "G" rating describes how the cancer cells look as compared to normal prostate cells. The less like normal they are, the higher the number. This is also known as the histologic classification. Like the M and N classifications, the higher the number the more abnormality that exists in the sample.
- GX: The grade cannot be assessed.
- G1: Well differentiated, (quite similar to normal prostate structure).
- G2: Moderate differentiation, (moderately different from normal structure).
- G3: Poorly differentiated, or undifferentiated (markedly different from normal structure)
Gleason Scoring
Gleason scoring takes tumor grading one step further in an attempt to predict how quickly your cancer will advance. During the Gleason scoring process, the pathologist takes the numbers for the two most representative types of cells seen in the sample and adds them together.
Similar to the "G" system described above, each representative cell type is given a number from one (normal) to five (very abnormal). For instance, when looking at a tumor sample, the pathologist sees a lot of normal cells and several moderately abnormal cells. He would give the normal cells a rating of one, and the moderately abnormal cells a grade of three. He would add 1+3 to give the sample a Gleason score of 4.
Thus a Gleason score will range from two to 10, with two being completely normal, and 10 very aggressive cancer. Generally Gleason scores of seven or above indicate a more serious prognosis with the chance that your tumors will be quite aggressive and spread quickly unless brought under control.
Summary
Suppose your doctor tells you that your prostate cancer is T2c, N0, M0 with a Gleason score of 4. This would mean that he found prostate cancer that is large enough to involve both lobes of your prostate, that it has not spread outside of the prostate, and has not spread to the local lymph nodes or to any other parts of the body. The Gleason score of 4 means that it is rated to be a relatively slow growing cancer. The TNM system describes how extensive your cancer is now. The tumor grading "G" rating and Gleason scores attempt to predict how quickly the cancer will spread if not brought under control.
Now that you understand how your prostate cancer has been classified, it is time to find out what treatments are appropriate for your specific situation. Continue to learn. Ask questions of your doctor. Get a second opinion about treatments. Join a support group. Involve your spouse and loved ones. An informed decision and a good support structure during this time of need are the two strongest allies you can have.
