Risk Groups and Lab Tests to Help Determine Risk from Localized Prostate Cancer

The stage of a prostate cancer can give an idea of how serious the cancer is likely to be. However, for localized prostate cancer (cancer that is still just in or around the prostate), doctors also use other ways to determine the risk that the cancer will grow and spread. Knowing this might help a man and his doctor when deciding if the cancer needs to be treated right away, as well as which treatment options might be best.

Ways to help determine the risk from localized prostate cancer include:

• Risk groups
• Molecular lab tests of biopsy samples

Prostate cancer risk groups

For prostate cancer that has not spread (stage I to III cancers), many doctors now use information about the cancer (such as the T category, initial PSA level, Grade Group, and prostate biopsy results) to place it into a risk group. This risk group can then be used to help determine treatment options.

Several expert groups have created risk classification systems for localized prostate cancer. One of the most commonly used systems, developed by the National Comprehensive Cancer Network (NCCN), divides localized prostate cancer into 6 risk groups:

Very-low-risk group

These prostate cancers are small, not felt on exam, can only be found in a small area of the prostate, and have not grown outside the prostate (cT1c). They have a Grade Group of 1 (Gleason score of 6 or less), a low PSA level (less than 10), and few other classification criteria. These cancers usually grow very slowly and almost never cause any symptoms or other health problems.

Low-risk group

Prostate cancers in this group have not yet grown outside of the prostate, have a Grade Group of 1 (Gleason score of 6 or less) and a low PSA level (less than 10), but they are slightly larger (cT1 to cT2a) than very-low-risk cancers. They are unlikely to cause symptoms or other health problems.

Intermediate-risk groups (favorable or unfavorable)

These prostate cancers can be felt on exam or can be seen on an imaging test. The cancer might be found in more than half of one side of the prostate (cT2b) or in both sides of the prostate (cT2c), and/or have a Grade Group of 2 or 3 (Gleason score of 7) and/or a PSA level between 10 and 20 ng/ml.

Additional factors are used to split these prostate cancers into favorable intermediate-risk and unfavorable intermediate-risk categories.

High-risk group

Prostate cancers in this group have only 1 of these high-risk features (and no very  high-risk features [see below]):

• The tumor has grown outside the prostate (cT3a).
• The cancer has a Grade Group of 4 or 5 (Gleason score 8 to 10).
• The initial PSA level is more than 20.

Very high-risk group

These prostate cancers have a very high risk for the tumor growing or spreading to nearby lymph nodes (or other parts of the body). These cancers have at least 1 of the following traits:

• The tumor has spread to the seminal vesicles (cT3b) or into other structures next to the prostate (cT4).
• The most common areas of cancer in the biopsy have a Gleason 5 pattern.
• More than 4 biopsy cores are Grade Group 4 or 5 (Gleason score 8 to 10).
• The cancer has 2 or 3 of the features found in the high-risk group (see above).

The risk group can help decide if any further tests should be done, as well as help guide treatment options. Cancers in lower-risk groups have a smaller chance of growing and spreading compared to those in higher-risk groups.

If you have prostate cancer that has not spread to nearby lymph nodes or to other parts of the body, talk to your doctor about which risk group your cancer falls into. This can help you better understand your treatment choices. To learn more about how risk groups are used, see Initial Treatment of Prostate Cancer, by Stage and Risk Group.

Lab tests to help determine if localized prostate cancer needs to be treated

Along with the risk groups above, some doctors are now using newer types of lab tests, known as genomic, molecular, or proteomic tests, to help predict how quickly a prostate cancer might grow or spread, and as a result, help decide what treatment options might be best. These tests look at which genes or proteins are active inside the prostate cancer cells.

Examples of such tests include:

• Decipher: This test measures the activity of certain genes in prostate cancer cells taken from a biopsy. These are used to create a risk score on a scale from 0 to 1, with a higher score indicating a cancer is more likely to spread to other parts of the body. This might be helpful in determining the best treatment options. For men who choose surgery (prostatectomy) to treat their cancer, another version of this test can be used to measure the activity of certain genes in prostate cancer cells from the surgery tissue. This can help determine the risk that the cancer will come back in other parts of the body after surgery, and as a result, if these men should consider further treatment.
• Oncotype DX Prostate: This test measures the activity of certain genes in prostate cancer cells taken from a biopsy and reports it as a score on a scale from 0 to 100. (Higher scores indicate a cancer that is more likely to grow and spread quickly, as well as a higher risk of dying from prostate cancer.)
• Prolaris: This test measures the activity of a different set of genes in prostate cancer cells taken from a biopsy and reports it as a score on a scale from 0 to 10. (Higher scores indicate a cancer that is more likely to grow and spread quickly, as well as a higher risk of dying from prostate cancer.)
• ProMark: This test measures the activity of a set of proteins in prostate cancer cells taken from a biopsy and reports it as a score that helps predict how likely a cancer is to grow and spread quickly.

If your doctor suggests using one of these tests to help determine your treatment options, have them explain what it can tell you, as well as how accurate it’s likely to be.

These and other new tests are also being studied to look for more areas where they can help with treatment decisions.