#Prostate_Cancer_Grading & #Prostate_Cancer_Gleason_Score …

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. To see other pages, use the menu.

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:

• The clinical stage is based on the results of tests done before surgery, which includes DRE, biopsy, x-rays, CT and/or MRI scans, and bone scans. X-rays, bone scans, CT scans, and MRI scans may not always be needed. They are recommended based on the PSA level; the size of the cancer, which includes its grade and volume; and the clinical stage of the cancer.
• The pathologic stage 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.

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.

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 lobe (part or side) of the prostate.
• T2b: The tumor involves more than one-half of 1 lobe of the prostate but not both lobes.
• T2c: The tumor has grown into both lobes of the prostate.

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

• T3a: The tumor has grown through the prostate capsule either on 1 side or on both sides of the prostate, or it has spread to the neck of the bladder. This is also known as an 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; 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.

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classification. See the table below the stage descriptions for all of the TNM combinations for each stage.

Stage I: Cancer is found in the prostate only, usually during another medical procedure. It cannot be felt during the DRE or seen on imaging tests. A stage I cancer is usually made up of cells that look more like healthy cells and is usually slow growing. 

Stage IIA and IIB: This stage describes a tumor that is too small to be felt or seen on imaging tests. Or, it describes a slightly larger tumor that can be felt during a DRE. The cancer has not spread outside of the prostate gland, but the cells are usually more abnormal and may tend to grow more quickly. A stage II cancer has not spread to lymph nodes or distant organs. 

Stage III: The cancer has spread beyond the outer layer of the prostate into nearby tissues. It may also have spread to the seminal vesicles. 

Stage IV: This stage describes any tumor that has spread to other parts of the body, such as the bladder, rectum, bone, liver, lungs, or lymph nodes. 

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.

Stage Grouping Chart

Stage	T	N	M
I	T1a, T1b, or T1c	N0	M0
	T2a	N0	M0
	Any T1 or T2a	N0	M0
IIA	T1a, T1b, or T1c	N0	M0
	T1a, T1b, or T1c	N0	M0
	T2a	N0	M0
	T2b	N0	M0
	T2b	N0	M0
IIB	T2c	N0	M0
	Any T1 or T2	N0	M0
	Any T1 or T2	N0	M0
III	T3a or T3b	N0	M0
IV	T4	N0	M0
	Any T	N1	M0
	Any T	Any N	M1

Used with permission of the AJCC, Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition, published by Springer-Verlag New York, www.cancerstaging.org. 

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 1 to 5. 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 doctor determines the main pattern of cell growth, which is the area where the cancer is most obvious; looks for any other less common pattern of growth; and gives each 1 a score. The scores are added together to come up with an overall score between 2 and 10.

The interpretation of the Gleason score by doctors has changed recently. Originally, doctors used a wide range of scores. Today, doctors no longer use Gleason scores of 5 or lower for cancer found with a biopsy. The lowest score used 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, described in the Treatment Options section, may be an option for a patient with a small tumor, low PSA level, and a Gleason score of 6. Patients with high Gleason score may need treatment that is more intensive, even if it does not appear that the cancer has 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.

Recently, pathologists have begun to adopt a new Gleason grouping system that arranges the scores into simplified groups that are translated as follows:

• Gleason Group I = Former Gleason 6
• Gleason Group II = Former Gleason 3 + 4 = 7
• Gleason Group III = Former Gleason 4 + 3 = 7
• Gleason Group IV = Former Gleason 8
• Gleason Group V = Former Gleason 9 or 10

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 Cancer Network (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 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. Or, use the menu to choose another section to continue reading this guide.