One of the most important parts of a prostate cancer diagnosis is finding out the stage of the cancer. The stage means how far the cancer has grown or spread.
Knowing the stage helps your doctor:
- Recommend the best treatment for you
- Decide if more tests are needed
- Estimate long-term results
- Discuss survival rates and follow-up care
Prostate cancer staging is complex. But understanding the basics can help you take an active role in your care.
How Is Prostate Cancer Staged?
Doctors use information from several tests to determine the stage of prostate cancer. These may include:
- Prostate-specific antigen (PSA) blood test
- Prostate biopsy
- Gleason score and Grade Group
- Physical exam, including a digital rectal exam (DRE)
- Imaging tests, such as:
- MRI
- CT scan
- Bone scan
- PSMA PET/CT scan
What is a Prostate Biopsy?
A prostate biopsy is a procedure in which small samples of tissue are removed from the prostate with a needle. A pathologist looks at these samples under a microscope to determine:
- If there are cancer cells
- How fast-growing (aggressive) the cancer may be
- The Gleason score and Grade Group
Your PSA level, biopsy results, and physical exam help your doctor estimate the risk that the cancer has or will spread.
For men with very-low-risk or low-risk prostate cancer cells, additional imaging tests are often not needed. This is because the chance of spread is small. Men with higher-risk cancer cells may need imaging tests to look for cancer outside the prostate.
The TNM System
The most commonly used staging system for prostate cancer is the American Joint Committee on Cancer (AJCC) TNM system.
TNM stands for:
- T (Tumor). This notes the size of the main tumor.
- N (Nodes). This notes if the cancer has spread to nearby lymph nodes.
- M (Metastasis). This notes if the cancer has spread to other parts of the body.
These categories are combined with your PSA level and Grade Group. Together these determine an overall stage, from Stage I to Stage IV.
Understanding the T Category
The T stage (T for tumor) describes the size and extent of the main tumor.
The clinical T (cT)category is how the tumor is felt or seen on an image. The cT can be based on:
- Digital rectal exam (DRE)
- MRI results
- Biopsy results
Clinical T (cT) findings include:
- T1. The cancer can’t be felt during an exam. It’s usually found because of an elevated PSA or during a prostate procedure.
- T2. The cancer can be felt. It is only inside the prostate.
- T3. The cancer has grown outside the prostate.
- T4. The cancer has spread into nearby tissues, such as the bladder or rectum.
The pathologic T (pT) category is how the cells look under a microscope. This is noted after surgery to remove the prostate (radical prostatectomy). A pathologist examines the prostate tissue under a microscope. The pathologic T category is often more accurate than the clinical T category.
Understanding the N Category
The N stage (N for node) describes if cancer has spread to nearby lymph nodes in the pelvis. Your doctor may determine the N category using any of these imaging tests:
- CT scan
- MRI
- PSMA PET/CT scan
If lymph nodes are removed during surgery to remove the prostate, the nodes are examined under a microscope. This will determine the pathologic N category.
Understanding the M Category
The M category (M for metastasis) describes if prostate cancer has spread to other parts of the body, such as:
- Lymph nodes outside the pelvis
- Bones
- Other organs, such as the lungs or liver
The M category is determined with imaging tests such as:
- Bone scan
- CT scan
- MRI
- PSMA PET/CT scan
In some cases a biopsy of the area where cancer cells are found (metastatic site) is done, but this is not always needed.
The Stages of Prostate Cancer
Stage I
Stage I prostate cancer:
- Is found only in the prostate
- Is usually low grade (Grade Group 1)
- Has a PSA less than 10 ng/mL
- Has not spread to lymph nodes or other parts of the body
These cancers are often slow growing.
Stage II
Stage II prostate cancer:
- Is found only in the prostate
- May have a higher PSA level
- May have a higher Grade Group
- Has not spread to lymph nodes or other organs
Stage II is divided into:
- Stage IIA
- Stage IIB
- Stage IIC
These subgroups reflect differences in PSA level, tumor size, and Grade Group.
Stage III
Stage III prostate cancer is considered locally advanced.
The cancer may:
- Have a higher PSA level
- Have a higher Grade Group
- Grow outside the prostate
- Spread into nearby tissues, such as the seminal vesicles
Stage III is divided into:
- Stage IIIA. This has a higher PSA level.
- Stage IIIB. This means the cancer has grown outside the prostate.
- Stage IIIC. This is Grade Group 5 (Gleason score 9 or 10).
Stage IV
Stage IV prostate cancer means the cancer has spread beyond the prostate. Stage IV includes:
- Stage IVA. The cancer has spread to nearby pelvic lymph nodes.
- Stage IVB. The cancer has spread to distant lymph nodes, bones, or other organs.
Bone is the most common place for metastatic prostate cancer to spread.
Examples of Staging Results
Below are some example staging results based on the methods above. Staging results are complex, so your doctor will explain your stage to you in detail.
Stage I – cT1N0M0. The tumor can’t be felt during an exam, and can’t be seen on ultrasound imaging; Grade Group 1 (Gleason score 6 or less), PSA less than 10 ng/mL.
Stage IIA – cT1N0M0. Grade Group 1, PSA less than 10-20 ng/mL.
Stage IIIB – T4N0M0. The cancer has grown outside the prostate gland and may have spread to nearby tissues such as the bladder or rectum; Grade Group 1 to 4, any PSA.
Stage IVB – any T, any N, M1. The cancer has spread to other parts of the body such as distant lymph nodes, bones, or other organs such as lungs or liver; any Grade Group, any PSA.
Understanding Survival Rates
Survival rates are only estimates. They are based on data from large groups of people. They can’t predict what will happen for any one person. There are many factors that affect how each person will fare with their cancer. And it’s important to remember that survival rates continue to improve as treatments advance.
According to data from the U.S. Surveillance, Epidemiology, and End Results (SEER) Program:
- Men with localized prostate cancer (Stages I to IIIA) have a 5-year relative survival rate of more than 99%.
- Men with regional disease (Stages IIIB to IVA) also have a 5-year relative survival rate of more than 99%.
- Men with metastatic prostate cancer (Stage IVB) have a 5-year relative survival rate of about 38%.
Questions to Ask Your Doctor
Understanding your stage can help you make treatment decisions. You may want to ask:
- What stage is my prostate cancer?
- What are my PSA level, Gleason score, and Grade Group?
- Has the cancer spread outside the prostate?
- Do I need additional imaging tests?
- How does my stage affect my treatment options?
- What are the goals of treatment?
Talking with Your Healthcare Team
Prostate cancer staging is complex, but knowing the basics can help you feel more in charge of your care. Ask your doctor to explain your stage in detail and what it means for your treatment options and follow-up care.