If prostate cancer is diagnosed, the doctor needs to determine the stage, or extent, of the cancer to plan the best treatment. Staging is used to find out whether the cancer has spread, and if so, to which parts of the body.
- Stage I: The cancer cannot be felt during a digital rectal exam or seen on a sonogram. It is found through a prostate biopsy or during surgery for another reason. The cancer is only in the prostate.
- Stage II: The tumor is more advanced or a higher grade than stage I, but the tumor is only in the prostate. It may be felt during a digital rectal exam or seen on a sonogram.
- Stage III: The tumor extends beyond the prostate wall. The tumor may have invaded the seminal vesicles, which sit on top of the prostate, but cancer cells have not spread to the lymph nodes.
- Stage IV: The tumor may have invaded the bladder, rectum or nearby structures (beyond the seminal vesicles). It may have spread to the lymph nodes, bones, or to other parts of the body.
Grades and Scores
As part of the staging process, a pathologist will assign a score to the prostate cancer based on how the cancer cells look under a microscope. Pathologists score prostate cancer according to the Gleason grade. The Gleason score indicates how aggressive the prostate cancer appears to be. A higher number means that the cancer is more aggressive and likely to spread. The Gleason score is determined by adding the two most common grades seen in a sample by the pathologist. Grades range from 3 (least aggressive) to 5 (most aggressive) and scores range from 6 (least aggressive) to 10 (most aggressive).
- A Gleason score of 6 is often considered low risk prostate cancer
- A Gleason score of 7 is often considered intermediate risk prostate cancer
- A Gleason score of 8-10 is often considered high risk prostate cancer