The Gleason score is a method of tumour classification used to classify the cancer into a stage which indicates how severe the cancer is and how likely it is that the treatment will be successful. The Gleason score is used to classify prostate cancer.

A numerical score is given to a cancer, from 2 to 10, which is the sum of two Gleason grades (depending on the level of changes the cells in the prostate cancer show). The Gleason score helps determine if a patient is suitable for high intensity focused ultrasound.