The Gleason scoring system for prostate cancer — named after Donald F. Gleason, the pathologist who devised it — grades tumors on their aggressiveness.

The scores are given out after cells are examined under a microscope. The grading system defines cancer cells solely by their architectural pattern. The two most common patterns are added together and their combined value indicates how benign or aggressive the cancer will turn out to be. The score consists of two numbers, a primary grade and a secondary grade. Each is given a value from 1 to 5, the higher numbers indicating a more aggressive cancer. The primary grade must be more than half of what is seen in total under the microscope. The most common score is a 3+3, or what is commonly known as a Gleason 6. It is the contention of Watchful Waiting that many Gleason 6 cancers do not need to be treated.

If you have been diagnosed with a Gleason 7 or above, this site is not for you.