Gleason scores are the most common and useful measure of the severity of prostate cancer. But, to a patient, the score can - at first- seem as confusing as it is scary.
Gleason grades range from 1 (low) to 5 (high). When a pathologist looks at your prostate tissue biopsy, he will give a primary grade to the area where the cancer is most prominent, and a secondary grade to the next most prominent site. Those grades are added to come up with a Gleason score of 1 to 10.