What’s My “Stage”?
A cancer’s stage is an assessment that takes into account a variety of factors: the cancer’s location, whether it has spread, or metastasized, and how much it’s interfering with normal body processes.
Generally, the stage of a person’s cancer is correlated with their chances for survival. But it’s important to understand that different types of cancer can have very different treatment success rates. Some types of cancer are highly treatable, and even patients diagnosed at stage IV can reasonably expect their treatment will be successful. Other types of cancer are very resistant to treatment, and even patients diagnosed at lower stages are in for a very tough fight. Prostate cancer is often highly treatable.
If your doctors confirm that you have prostate cancer, they will begin a process of assessing several factors to determine your stage. This will help them recommend the best possible treatments, customized for you.
Staging Your Disease
There are 4 main components to staging prostate cancer:
- Your PSA level
- The grade of your tumor (done via biopsy)
- The stage of your tumor (termed the T-stage for the prostate tumor)—for example, is the prostate cancer contained completely within the prostate?
- Whether the cancer has spread, or metastasized, to lymph nodes (termed the “N-stage” for nodes) or bones or other organs (termed the “M-stage” for metastasis).
Here is more detail about these components:
1. PSA: Your PSA level.
This is where PSA testing for screening and PSA testing for staging and diagnosis diverge. For screening purposes, doctors are simply looking for a higher-than-expected level, or for a level that’s higher than it was at your previous screening tests. Once cancer has been diagnosed, the PSA level can be tracked more regularly to use as a barometer of how your cancer is behaving and how treatment is working.
In the initial phase, at staging, your doctor will start by looking at the results of your most recent PSA tests or ordering a new test.
Learn more about what the PSA test measures.
2. Grade: How aggressive is the cancer?
The pathology team will take a biopsy sample and prepare it with chemicals, then make extremely fine slices of the tissue to examine under the microscope. If prostate cancer is found when looking at biopsied tissue under a microscope, the pathologist assigns a grade to the cancer. There are 2 grading systems currently in use, which can be confusing for patients.
The classical grading system for prostate cancer is called the Gleason score, which ranges from 6 to 10 (6 is low grade, 7 is intermediate grade, and a score of 8 to 10 is high grade).
In 2014, the International Society of Urological Pathology (ISUP) defined the new, simpler Grade Group system, ranging from 1 (low) to 5 (very high).
Many medical centers report both the Gleason score and the Grade Group, but there may be some that report only the Gleason score.
3. Pathological stage: A look at the actual cancer cells and their distribution within the pelvic area.
This system assesses how pervasive the cancer cells are within and around the prostate. These stages begin at T2.
T2: The tumor is located in the prostate only.
T3: The tumor extends outside the prostate.
>T3b: The tumor has begun to grow in the seminal vesicles.
T4: The tumor has grown into other neighboring structures, like the bladder, the rectum, or the pelvic wall.
4. Metastases: Whether the cancer has spread.
The spread of cancer is measured in two ways: by lymph node involvement, and by its appearance in other organs or parts of the body, or metastasis. In the U.S., this is most commonly done with a computed tomography (CT) scan or an MRI and a bone scan. Newer and more sensitive imaging technologies include molecular PET imaging, such PSMA PET.
Lymph node staging, or N-staging, determines whether the cancer is present in nearby lymph nodes. Lymph nodes are tiny organs that are part of the immune system.
NX: The regional lymph nodes cannot be evaluated.
N0: The cancer has not spread to lymph nodes in the immediate area.
N1: The cancer has spread to lymph nodes in the pelvic region.
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: Metastasis cannot be evaluated.
M0: The cancer has not metastasized beyond the immediate prostate region.
M1: The cancer has metastasized deeper into the body.
- M1a: The cancer has spread to lymph nodes away from the groin area.
- 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 bones.
The combination of your full staging results, including your grade and your T, N, and M stages, paints a more complete picture of how the cancer is progressing. This enables your doctors to determine which treatments have the best chance or controlling or eradicating your cancer.