Understanding Prostate Cancer Risk Groups
If you have been diagnosed with prostate cancer, the next step is finding out how aggressive (fast-growing) the cancer is and if it has spread beyond the prostate.
Many people are familiar with cancer stages (Stages 1 through 4). Prostate cancer is also grouped by risk level. This is called risk stratification.
Knowing your risk group helps your healthcare team decide:
- If you need more tests
- Which treatment options may be best for you
- How likely the cancer is to grow or spread
How Is Prostate Cancer Risk Determined?
Most men are diagnosed after:
- A higher-than-normal PSA (prostate-specific antigen) blood test result
- A prostate biopsy
- Sometimes an MRI before the biopsy
A biopsy confirms if the cells are cancer. The information from the biopsy, along with other test results, is used to place the cancer into a risk group.
Your healthcare provider looks at three main factors:
- Your biopsy results
- Your PSA level
- The findings from a digital rectal exam (DRE)
Together, these help estimate how likely the cancer is to spread outside the prostate.
Biopsy Results
A pathologist examines the biopsy samples under a microscope to see how abnormal the cancer cells look. This is called the grade of the cancer.
The grade may be reported as:
- ISUP Grade Group 1 to 5. Grade Group 1 is the least aggressive. Grade Group 5 is the most aggressive.
- Gleason score. The scores range from 6 to 10. A Gleason score of 6 is the least aggressive. A score of 10 is the most aggressive.
Higher grades mean the cancer is more likely to grow and spread.
PSA Level
Your PSA blood test also helps determine your risk group.
PSA levels are generally divided into three ranges:
- Less than 10 ng/mL
- 10 to 20 ng/mL
- More than 20 ng/mL
Higher PSA levels may suggest a greater chance that the cancer has grown beyond the prostate.
Digital Rectal Exam (DRE)
During a digital rectal exam, your healthcare provider gently feels the prostate through the rectum.
The exam may show that:
- The cancer cannot be felt.
- The cancer is small and appears to be only in the prostate.
- The cancer may have grown outside the prostate.
- The cancer may have spread into nearby tissues, such as the bladder, pelvis, or rectum.
How Risk Groups Are Created
Healthcare providers combine these to place your cancer into a risk group:
- Biopsy grade
- PSA level
- Digital rectal exam findings
Several systems are used to classify prostate cancer risk. These include the D'Amico, American Urological Association (AUA), and National Comprehensive Cancer Network (NCCN) systems. Although these systems differ slightly, they all help guide treatment decisions.
Very Low- and Low-Risk Prostate Cancer
Low-risk prostate cancer usually includes:
- Cells that are ISUP Grade Group 1 (Gleason score 6)
- PSA less than 10 ng/mL
- Cancer that cannot be felt or is small and confined to the prostate
Some men have only a very small amount of cancer found on their biopsy. They may be classified as having very low-risk prostate cancer.
People with very low- or low-risk prostate cancer usually do not need additional imaging tests. Many are good candidates for active surveillance. This means closely monitoring the cancer with regular checkups instead of treating it right away.
Intermediate-Risk Prostate Cancer
Intermediate-risk prostate cancer is when you have one or more of these:
- Cells that are ISUP Grade Group 2 or 3
- PSA between 10 and 20 ng/mL
- Cancer that is larger but still appears to be only in the prostate on a digital rectal exam
Intermediate-risk prostate cancer may be described as favorable or unfavorable. This depends on factors such as:
- How many intermediate-risk features it has
- How many biopsy samples have cancer cells
Some men with intermediate-risk prostate cancer will need imaging tests to check if the cancer has spread.
These tests may include:
- Bone scan
- CT scan
- MRI
- PET scan
If the cancer has not spread, treatment is often recommended. This may include:
- Surgery
- Radiation therapy
For some men - especially those with other serious health conditions or favorable intermediate-risk disease - active surveillance may also be an option.
High-Risk Prostate Cancer
High-risk prostate cancer includes any of the following:
- Cells that are ISUP Grade Group 4 or 5
- PSA greater than 20 ng/mL
- Signs on a digital rectal exam that the cancer has grown outside the prostate
People with high-risk prostate cancer usually need imaging tests to look for signs that the cancer has spread.
Treatment often involves more than one approach, such as:
- Surgery
- Radiation therapy
- Hormone therapy
If the Cancer Has Spread
Sometimes imaging tests show that prostate cancer has spread to any of these:
- Nearby lymph nodes
- Lymph nodes in other parts of the body
- Bones
- Other organs
This is called regional or metastatic prostate cancer.
Some men may still benefit from treatment directed at the prostate. However, treatment usually focuses on systemic therapy, such as hormone therapy. Hormone therapy for this stage is usually combined with other medications, such as newer hormone-blocking drugs or chemotherapy, rather than used alone. Systemic treatments travel throughout the body to treat cancer cells wherever they may be.
Talking with Your Healthcare Team
Risk stratification helps your healthcare team understand how likely your prostate cancer is to grow or spread. Knowing your risk group helps guide decisions about:
- If you need more imaging tests
- Which treatments may be best for you
- If active surveillance may be an option
Talk to your healthcare team if you are unsure about any test results, or you need to ask more questions.