If prostate cancer is diagnosed, the doctor needs to determine the stage, or extent, of the cancer to plan the best treatment. Staging is a careful attempt to find out whether the cancer has spread, and if so, to what parts of the body.
Grades and Scores
- Stage I: The cancer can't be felt during a digital rectal exam, and it can't be seen on a sonogram. It's found by doing a prostate biopsy or when surgery is done 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 doesn't extend beyond the prostate. It may be felt during a digital rectal exam, or it may be 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 haven't 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.
If prostate cancer cells are found in the prostate, the cells will be graded by a pathologist to understand how aggressive the cancer is. Aggressive cancer cells look and behave very differently than normal cells; they are more likely to spread so they receive a higher grade.
Pathologists score prostate cancer according to the Gleason grade, which grades the prostate cancer cells based on how they look under the microscope. The Gleason score indicates how aggressive the prostate cancer appears to be. The score is determined by adding the two most common grades seen in a specimen by a 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