What is Gleason Score?
In 1966, Donald Gleason introduced a standardized system for scoring prostate cancer, based on glandular architecture at low to medium power. The grades range from 1 to 5. The Gleason score is the sum of the two most prevalent grades present (2 to 10). The Gleason score was shown to predict outcome in prostate cancer.
Currently, recommendations are based on 2005 International Society of Urological Pathology Consensus Conference on Gleason Grading. The score is based on a pathologist's review of the prostate tissue under a microscope.
Gleason grade 1 and 2 are extremely rare, typically only diagnosed by expert urologic pathologists, and often debated whether they even should be classified as cancer. The vast majority of cancers detected on needle biopsy are Gleason grade 3.
Grade 3 is defined as tumor composed of discrete glands.
Grade 4 is defined as fused glands.
Grade 5 pattern shows an absence of glands. Instead there are single cells or a solid pattern of tumor.
Gleason factors into staging.
Gleason score and PSA are the most important factors that impact treatment choice and prognosis. Studies have shown that using a cut point of Gleason score 7 best predicted biochemical recurrence. Controversy exists on the preferred mode of therapy for Gleason score 7 (intermediate grade).
Every tumor is unique. Make sure to ask your urologist about your tumor characteristics. Shared decision making is the best course. Gleason score will be in the pathology report. Get a copy and ask questions.