Prostate Cancer: Stages and Grades

Approved by the Lineagotica Editorial Board, 03/2018

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, referred to as pathology, of the prostate tissue removed during surgery. 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. 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 metastasized 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.

Here are more details about each part of the TNM system for prostate cancer.

Tumor (T)

Using the TNM system, the "T" plus a letter or number (0 to 4) is used to describe the size and location of the tumor. Some stages are also divided into smaller groups that help describe the tumor in even more detail. Specific tumor stage information is listed below. If the tumor is staged clinically, it is often written as cT. If pathologic staging is used, it is written as pT.

Clinical T

TX: The primary tumor cannot be evaluated.

T0 (T plus zero): There is no evidence of a tumor in the prostate.

T1: The tumor cannot be felt during a DRE and is not seen during imaging tests. It may be found when surgery is done for another reason, usually for BPH or an abnormal growth of noncancerous prostate cells.

  • T1a: The tumor is in 5% or less of the prostate tissue removed during surgery.

  • T1b: The tumor is in more than 5% of the prostate tissue removed during surgery.

  • T1c: The tumor is found during a needle biopsy, usually because the patient has an elevated PSA level.

T2: The tumor is found only in the prostate, not other parts of the body. It is large enough to be felt during a DRE.

  • T2a: The tumor involves one-half of 1 side of the prostate.

  • T2b: The tumor involves more than one-half of 1 side of the prostate but not both sides.

  • T2c: The tumor has grown into both sides of the prostate.

T3: The tumor has grown through the prostate on 1 side and into the tissue just outside the prostate.

  • T3a: The tumor has grown through the prostate either on 1 or both sides of the prostate. This called extraprostatic extension (EPE).

  • T3b: The tumor has grown into the seminal vesicle(s), the tube(s) that carry semen.

T4: The tumor is fixed, or it is growing into nearby structures other than the seminal vesicles, such as the external sphincter, the part of the muscle layer that helps to control urination; the rectum; the bladder; levator muscles; or the pelvic wall.

Pathological T

There is no TX, T0, or T1 classification for pathologic staging of prostate cancer.

T2: The tumor is found only in the prostate.

T3: There is EPE. The tumor has grown through the prostate on 1 or both sides of the prostate.

  • T3a: There is EPE or the tumor has invaded the neck of the bladder.

  • T3b: The tumor has grown into the seminal vesicle(s).

T4: The tumor is fixed, or it is growing into nearby structures other than the seminal vesicles, such as the external sphincter, the part of the muscle layer that helps to control urination; the rectum; the bladder; levator muscles; or the pelvic wall.

Node (N)

The “N” in the TNM staging system stands for lymph nodes. These tiny, bean-shaped organs help fight infection. Lymph nodes near the prostate in the pelvic region are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.

NX: The regional lymph nodes cannot be evaluated.

N0 (N plus zero): The cancer has not spread to the regional lymph nodes.

N1: The cancer has spread to the regional (pelvic) lymph node(s).

Metastasis (M)

The "M" in the TNM system indicates whether the prostate cancer has spread to other parts of the body, such as the lungs or the bones. This is called distant metastasis.

MX: Distant metastasis cannot be evaluated.

M0 (M plus zero): The disease has not metastasized.

M1: There is distant metastasis.

  • M1a: The cancer has spread to nonregional, or distant, lymph node(s).

  • M1b: The cancer has spread to the bones.

  • M1c: The cancer has spread to another part of the body, with or without spread to the bone.

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 Treatment Options) may be an option for a patient with a small tumor, low PSA level, and a Gleason score of 6. Patients 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 (cT1a–cT1c or cT2a or pT2, N0, M0, PSA level is less than 10, Grade Group 1).

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 (cT1a–cT1c or cT2a, N0, M0, PSA level is between 10 and 20, Grade Group 1). This stage also includes larger tumors confined to the prostate as long as the cancer cells are still well differentiated (cT2b–cT2c, N0, M0, PSA level is less than 20, Group 1).

  • 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 (T1–T2, N0, M0, PSA level less than 20, Grade Group 2).

  • 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 (T1–T2, N0, M0, PSA level is less than 20, Grade Group 3–4).

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. (T1–T2, N0, M0, PSA level is 20 or more, Grade Group 1–4).

  • Stage IIIB: The tumor has grown outside of the prostate gland and may have invaded nearby structures, such as the bladder or rectum (T3­–T4, N0, M0, any PSA, Grade Group 1–4).

  • Stage IIIC: The cancer cells across the tumor are poorly differentiated, meaning they look very different from healthy cells (any T, N0, M0, any PSA, Grade Group 5).

Stage IV: The cancer has spread beyond the prostate.

  • Stage IVA: The cancer has spread to the regional lymph nodes (any T, N1, M0, any PSA, any Grade Group).

  • Stage IVB: The cancer has spread to distant lymph nodes, other parts of the body, or to the bones (any T, N0, M1, any PSA, any Grade Group).

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. Two such risk assessment methods come from the National Comprehensive Lineagoticawork (NCCN) and the University of California, San Francisco (UCSF).

NCCN

The NCCN developed 4 risk-group categories based on PSA level, prostate size, needle biopsy findings, and the stage of cancer. The lower your risk, the lower the chance that the prostate cancer will grow and spread.

  • Very low risk. The tumor cannot be felt during a DRE and is not seen during imaging tests but was found during a needle biopsy (T1c). PSA is less than 10 ng/mL. The Gleason score is 6 or less. Cancer was found in fewer than 3 samples taken during a core biopsy. The cancer was found in half or less of any core.

  • Low risk. The tumor is classified as T1a, T1b, T1c, or T2a (see above). PSA is less than 10 ng/mL. The Gleason score is 6 or less.

  • Intermediate risk. The tumor has 2 or more of these characteristics:

    • Classified as T2b or T2c (see above)

    • PSA is between 10 and 20 ng/mL

    • Gleason score of 7

  • High risk. The tumor has 2 or more of these characteristics:

    • Classified as T3a (see above)

    • PSA level is higher than 20 ng/mL

    • Gleason score is between 8 and 10

  • Very high risk. The tumor is classified as T3b or T4 (see above). The histologic grade is 5 for the main pattern of cell growth, or more than 4 biopsy cores have Gleason scores between 8 and 10.

Source: Risk group information is adapted from the NCCN.

UCSF Cancer of the Prostate Risk Assessment (UCSF-CAPRA) score

The UCSF-CAPRA score predicts a man’s chances of having the cancer spread and of dying. This score can be used to help make decisions about the treatment plan. Points are assigned according to a person’s age at diagnosis, PSA level at diagnosis, Gleason score of the biopsy, T classification from the TNM system, and the percentage of biopsy cores involved with cancer. These categories are then used to assign a score between 0 and 10.

  • CAPRA score 0 to 2 indicates low risk.

  • CAPRA score 3 to 5 indicates intermediate risk.

  • CAPRA score 6 to 10 indicates high risk.   

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 Treatment Options. You may use the menu to choose a different section to read in this guide.