Glossary Term:


Gleason score or Gleason sum



the sum of the 2 Gleason grades used classify prostate cancer based on how the cells look under the microscope. Because prostate cancers often have areas with different grades, a grade is assigned to the 2 areas that make up most of the cancer. These 2 grades are added to give a Gleason score between 2 and 10. This is used along with other information to stage the cancer. The higher the Gleason score, the faster the cancer is likely to grow and the more likely it is to spread beyond the prostate. See also Gleason grade, prostate, staging.