The Gleason Grading System

If your diagnostic tests and other examinations reveal a malignant tumor of the prostate, your physician may use the Gleason grading system to help describe the appearance of the cancerous prostate tissue. In order to do this, a pathologist will look at the biopsied prostate tissue under a microscope. He or she will examine the way that the cancerous cells look compared to normal prostate cells.

If the cancerous cells appear to resemble the normal prostate tissue very closely, they are said to be very well differentiated and are considered to be Gleason grade 1. This means that the tumor is not expected to be fast growing.

On the other hand, if the cells in question look fairly irregular and very different from the normal prostate cells, then they are very poorly differentiated and are assigned a Gleason grade 5.

Grades 2-4 are used for tumors that fall between grades 1 and 5, with higher numbers corresponding to faster growing tumors.

Because prostate cancer tissue is often made up of areas that have different grades, the pathologist will closely examine the areas that make up the largest portion of the tissue. Gleason grades are then given to the two most commonly occurring patterns of cells.

Once the two grades have been assigned, a Gleason score can be determined by adding together the two Gleason Grades. The Gleason score that results will be a number from 2 to 10.

Gleason scores should be discussed with your doctor. Your doctor can explain what your Gleason score, along with your other test reports, mean for you as an individual.

Scores on the higher end of the Gleason grading system (7 through 10) usually indicate a more serious prognosis.