The Gleason scale, developed by physician Donald Gleason in the 1960s, provides a score that helps predict the aggressiveness of prostate cancer. Pathologists assign two grades to prostate cancers ranging from one to five based on how they look under a microscope. This is called the Gleason score. The first, called the primary grade, is determined by observing the area where the prostate cancer cells are most prominent. The secondary grade considers the area where the cells are almost as prominent. These two numbers added together produce the total Gleason sum. This is a number between two and 10. A higher score means the cancer is more likely to spread.
A Gleason score between two and six means the cancer is likely to grow and spread very slowly. If the cancer is small, many years may pass before it becomes a problem. Thus, you may never need cancer treatment.
A Gleason score of seven means the cancer is likely to grow and spread at a modest pace. If the cancer is small, several years may pass before it becomes a problem. To prevent problems, treatment is needed.
A Gleason score between eight and 10 signifies the cancer is likely to grow and spread fast. If the cancer is small, a few years may pass before the cancer becomes a problem. To prevent problems, treatment is needed now.