What is the Gleason system?
The Gleason System is used in grading prostate cancer. If your diagnostic tests and other examinations reveal a malignant tumor, 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 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 a faster growing tumor. Because prostate
