Site Map

Gleason grading system

Prostate cancer - Gleason; Adenocarcinoma prostate - Gleason; Gleason grade; Gleason score; Gleason group; Prostate cancer - 5 grade group

Prostate cancer is diagnosed after a biopsy. One or more tissue samples are taken from the prostate and examined under the microscope.

The Gleason grading system refers to how abnormal your prostate cancer cells look and how likely the cancer is to advance and spread. A lower Gleason grade means that the cancer is slower growing and not aggressive.

I Would Like to Learn About:

Gleason Score

The first step in determining the Gleason grade is to determine the Gleason score.

  1. When looking at cells under the microscope, the doctor assigns a number (or grade) to the prostate cancer cells between 1 and 5.
  2. This grade is based on how abnormal the cells appear. Grade 1 means that the cells look almost like normal prostate cells. Grade 5 means that the cells look very different from normal prostate cells.
  3. Most prostate cancers contain cells that are different grades. So the two most common grades are used.
  4. The Gleason score is determined by adding the two most common grades. For example, the most common grade of the cells in a tissue sample may be grade 3 cells, followed by grade 4 cells. The Gleason score for this sample would be 7.

Higher numbers indicate a faster growing cancer that is more likely to spread.

Currently the lowest score assigned to a tumor is grade 3. Grades below 3 show normal to near normal cells. Most cancers have a Gleason score (the sum of the two most common grades) between 6 (Gleason scores of 3+3) and 7 (Gleason scores of 3+4 or 4+3).

Gleason Grading System

Sometimes, it can be hard to predict how well people will do based just on their Gleason scores alone.

A new 5 Grade Group System has recently been created. This system is a better way to describe how a cancer will behave and respond to treatment.

A lower group indicates a better chance for successful treatment than a higher group. A higher group means that more of the cancer cells look different from normal cells. A higher group also means that it is more likely that the tumor will spread aggressively.

Grading helps you and your doctor determine your treatment options, along with:


Bostwick DG, Cheng L. Neoplasms of the prostate. In: Cheng L, MacLennan GT, Bostwick DG, eds. Urologic Surgical Pathology. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 9.

Epstein JI. Pathology of prostatic neoplasia. In: Partin AW, Dmochowski RR, Kavoussi LR, Peters CA, eds. Campbell-Walsh-Wein Urology. 12th ed. Philadelphia, PA: Elsevier; 2021:chap 151.

National Cancer Institute website. Prostate cancer treatment (PDQ) – health professional version. Updated July 22, 2020. Accessed August 10, 2020.


Review Date: 5/15/2020  

Reviewed By: Sovrin M. Shah, MD, Assistant Professor, Department of Urology, The Icahn School of Medicine at Mount Sinai, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

ADAM Quality Logo

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider ( URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complies with the HONcode standard for trustworthy health information: verify here.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2022 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.