Prostate Cancer: Stages and Grades

Approved by the Cancer.Net Editorial Board, 11/2019

ON THIS PAGE: You will learn about how doctors describe a cancer’s growth or spread, as well as what the cancer cells look like under a microscope. This is called the stage and grade. Use the menu to see other pages.

Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting other parts of the body.

Doctors use diagnostic tests to find out the cancer's stage, so staging may not be complete until all of the tests are finished. Staging for prostate cancer also involves looking at test results to find out if the cancer has spread from the prostate to other parts of the body. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis, which is the chance of recovery. There are different stage descriptions for different types of cancer.

There are 2 types of staging for prostate cancer:

  • Clinical staging. This is based on the results of DRE, PSA testing, and Gleason score (see “Gleason score for grading prostate cancer” below). These test results will help determine whether x-rays, bone scans, CT scans, or MRI are also needed. If scans are needed, they can add more information to help the doctor figure out the clinical stage.

  • Pathologic staging. This is based on information found during surgery, plus the laboratory results of the prostate tissue removed during surgery, also called the pathology. The surgery often includes the removal of the entire prostate and some lymph nodes. Examination of the removed lymph nodes can provide more information for pathologic staging.

TNM staging system

One tool that doctors use to describe the stage is the TNM system. This system is developed by the American Joint Committee on Cancer. (Please note that this link takes you to a different website.) Doctors use the results from diagnostic tests and scans to answer these questions:

  • Tumor (T): How large is the primary tumor? Where is it located?

  • Node (N): Has the tumor spread to the lymph nodes? If so, where and how many?

  • Metastasis (M): Has the cancer spread to other parts of the body? If so, where and how much?

The results are combined to determine the stage of cancer for each person. There are 5 stages: stage 0 (zero) and stages I through IV (1 through 4). The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.

Gleason score for grading prostate cancer

Prostate cancer is also given a grade called a Gleason score. This score is based on how much the cancer looks like healthy tissue when viewed under a microscope. Less aggressive tumors generally look more like healthy tissue. Tumors that are more aggressive are likely to grow and spread to other parts of the body. They look less like healthy tissue.

The Gleason scoring system is the most common prostate cancer grading system used. The pathologist looks at how the cancer cells are arranged in the prostate and assigns a score on a scale of 3 to 5 from 2 different locations. Cancer cells that look similar to healthy cells receive a low score. Cancer cells that look less like healthy cells or look more aggressive receive a higher score. To assign the numbers, the pathologist determines the main pattern of cell growth, which is the area where the cancer is most obvious and looks for another area of growth. The doctor then gives each area a score from 3 to 5. The scores are added together to come up with an overall score between 6 and 10.

Gleason scores of 5 or lower are not used. The lowest Gleason score is 6, which is a low-grade cancer. A Gleason score of 7 is a medium-grade cancer, and a score of 8, 9, or 10 is a high-grade cancer. A lower-grade cancer grows more slowly and is less likely to spread than a high-grade cancer.

Doctors look at the Gleason score in addition to stage to help plan treatment. For example, active surveillance (see Types of Treatment) may be an option for someone with a small tumor, low PSA level, and a Gleason score of 6. People with a higher Gleason score may need treatment that is more intensive, even if the cancer is not large or has not spread.

  • Gleason X: The Gleason score cannot be determined.

  • Gleason 6 or lower: The cells are well differentiated, meaning they look similar to healthy cells.

  • Gleason 7: The cells are moderately differentiated, meaning they look somewhat similar to healthy cells.

  • Gleason 8, 9, or 10: The cells are poorly differentiated or undifferentiated, meaning they look very different from healthy cells.

Gleason scores are often grouped into simplified Grade Groups:

  • Grade Group 1 = Gleason 6

  • Grade Group 2 = Gleason 3 + 4 = 7

  • Grade Group 3 = Gleason 4 + 3 = 7

  • Gleason Group 4 = Gleason 8

  • Gleason Group 5 = Gleason 9 or 10

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classifications. Staging also includes the PSA level (see Screening) and Grade Group.

Stage I: Cancer in this early stage is usually slow growing. The tumor cannot be felt and involves one-half of 1 side of the prostate or even less than that. PSA levels are low. The cancer cells are well differentiated, meaning they look like healthy cells.

Stage II: The tumor is found only in the prostate. PSA levels are medium or low. Stage II prostate cancer is small but may have an increasing risk of growing and spreading.

  • Stage IIA: The tumor cannot be felt and involves half of 1 side of the prostate or even less than that. PSA levels are medium, and the cancer cells are well differentiated. This stage also includes larger tumors confined to the prostate as long as the cancer cells are still well differentiated.

  • Stage IIB: The tumor is found only inside the prostate, and it may be large enough to be felt during DRE. The PSA level is medium. The cancer cells are moderately differentiated.

  • Stage IIC: The tumor is found only inside the prostate, and it may be large enough to be felt during DRE. The PSA level is medium. The cancer cells may be moderately or poorly differentiated.

Stage III: PSA levels are high, the tumor is growing, or the cancer is high grade. These all indicate a locally advanced cancer that is likely to grow and spread.

  • Stage IIIA: The cancer has spread beyond the outer layer of the prostate into nearby tissues. It may also have spread to the seminal vesicles. The PSA level is high.

  • Stage IIIB: The tumor has grown outside of the prostate gland and may have invaded nearby structures, such as the bladder or rectum.

  • Stage IIIC: The cancer cells across the tumor are poorly differentiated, meaning they look very different from healthy cells.

Stage IV: The cancer has spread beyond the prostate.

  • Stage IVA: The cancer has spread to the regional lymph nodes.

  • Stage IVB: The cancer has spread to distant lymph nodes, other parts of the body, or to the bones.

Recurrent: Recurrent prostate cancer is cancer that has come back after treatment. It may come back in the prostate area again or in other parts of the body. If the cancer does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.

Used with permission of the American College of Surgeons, Chicago, Illinois. The original and primary source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017), published by Springer International Publishing.

Prostate cancer risk groups

In addition to stage, doctors use other prognostic factors to help plan the best treatment and predict how successful treatment will be. The National Comprehensive Cancer Network (NCCN) risk group categories and the Cancer of the Prostate Risk Assessment (CAPRA) risk score from University of California, San Francisco, are 2 examples of prostate cancer risk groups.

Information about the cancer’s stage and other prognostic factors will help the doctor recommend a specific treatment plan. The next section in this guide is Types of Treatment. Use the menu to choose a different section to read in this guide.