Understanding Your Stage of Prostate Cancer
Stage is the word doctors use to communicate the size of a cancerous tumor and where and how far it has spread. The first place cancer is found in the body is called the primary site or primary tumor. When a cancer spreads, it’s said to have metastasized. There are 2 types of stages of cancer, clinical and pathological.
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The clinical stage helps your doctor decide on the best options for you. For prostate cancer, your clinical stage is determined from a digital rectal exam (DRE), biopsies, and scans.
How Prostate Cancer Spreads
The first places that prostate cancer usually spreads are to nearby organs such as your bladder, seminal vesicles (which produce semen), rectum, and pelvis wall. Once cancer moves away from the prostate, it often goes into the nearby lymph nodes in your pelvis. In some cases, it spreads to distant parts of the body, mainly to the bones. The bones most often affected are the spine and ribs. In its later stages, prostate cancer may spread to the liver, lungs, bone marrow, or other lymph nodes. This is less common.
When prostate cancer has spread to another part of the body, it’s not considered a new cancer. For instance, if prostate cancer spreads to the bones, it’s not considered bone cancer. It’s called metastatic prostate cancer.
There are also several kinds of cancer--such as kidney cancer--that can spread to your prostate. When this happens, the cancer is not called prostate cancer. This is because cancer is usually named for the site of the original tumor. For example, if kidney cancer spreads to your prostate, it will be treated as metastatic kidney cancer, not as prostate cancer.
The Stages of Prostate Cancer
Doctors need to know what stage your prostate cancer is in to decide what treatment to recommend. The stage is based on the size and extent of your tumor, the number of lymph nodes involved, and how far the cancer has spread. Your oncologist gets this information from your DRE, biopsies, and scans. The most common way doctors describe the stage is with the TNM system.
The TNM System
The TNM System is a standard system for describing the extent of a cancer’s growth. It is the most common system used to stage prostate cancer. It was developed by the International Union Against Cancer and the American Joint Committee on Cancer (AJCC). Here’s what the letters stand for in the TNM System.
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T refers to the size of the tumor in the prostate.
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N refers to whether the lymph nodes in the area of the prostate have become cancerous.
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M refers to whether the cancer has spread (metastasized) to other, distant organs in the body, such as your bones, liver, or lungs.
Your oncologist assigns numerical values from X to 3 to your T, N, and M stages. These letter and number combinations are called stage groupings. They’re used to determine your overall disease stage.
Stage Groupings of Prostate Cancer
The most commonly used system to stage cancer is called the American Joint Committee on Cancer (AJCC) TNM classification. This system defines cancers by Roman numbers 0 through IV. The lower the number, the less the cancer has spread. The higher the number, the more the cancer has spread. These are the stages of prostate cancer and their definitions. Be sure to ask your doctor to help explain your cancer’s stage to you. Each TNM category, with its assigned numerical value from X to 3, falls into one of these stages. An ‘X’ means that the T, N, or M cannot be determined.
Stage I
Tumors at this stage cannot be felt by a DRE, nor do they show up on imaging tests. The cancer does show up in a biopsy. It’s typically found during surgery for another problem, such as BPH. BPH is the overgrowth of normal prostate cells, but it’s not cancer. Or the cancer can be found after a high PSA level is drawn. The cancer hasn’t spread to lymph nodes or organs. You may hear your doctor use these TNM terms for this stage: T1a-c, N0, and M0.
Stage II
The cancer has not spread to the lymph nodes or other parts of the body. Tumors may be felt by a DRE. They may be seen during a transrectal ultrasound. You may hear your doctor use these TNM terms for this stage: T2, N0, and MO.
Stage III
The tumor has spread outside of the prostate. It may involve some of the glands that produce semen, called the seminal vesicles. It has not spread to your lymph nodes or anywhere else in your body. You may hear your doctor use these TNM terms for this stage: T3, N0, and MO.
Stage IV
The tumor has spread beyond the prostate and seminal vesicles. It may also be in your bladder, rectum, surrounding muscle, pelvis wall, lymph nodes, or other parts of your body. You may hear your doctor use these TNM terms for this stage: T4, N1-3, and M+.
Stages I and II are sometimes referred to as early-stage prostate cancer. Stages III and IV are sometimes called advanced prostate cancer.
Whitmore-Jewett System
Another staging system that is used is the Whitmore-Jewett System. The stages in this system are assigned the letters A through D, rather than numbers, and are described below. Here’s an overview of this system.
Stage A
The tumor was found during a transurethral prostatectomy (TURP), a type of surgery that removes bits of the prostate that are blocking urine flow. It’s often used to help men who have BPH. It’s classified as A1 if less than 5% of the tumor had cancer in it. It’s classified as A2 if more than 5% of the tumor had cancer in it.
Stage B
The tumor can be felt, and it’s confined within the prostate. Depending on how many lobes of the prostate are involved, your doctor will further classify is as B1N, B1, or B2.
Stage C
The tumor extends beyond the prostate capsule. The capsule is the outer layer of the prostate. Depending on how the seminal vesicles are involved, your doctor will further classify it as C1 or C2. The seminal vesicles are located above and behind the prostate. They help produce fluid that is part of the ejaculate.
Stage D
The tumor has spread. This is also called metastatic disease. Stage D is broken down into these categories:
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D0: Only the prostatic acid phosphatase level is high.
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D1: The cancer has spread into the lymph nodes in the pelvis.
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D1.5: You’ve had local treatment, but your PSA level is still increasing.
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D2: The cancer has spread to distant areas of the body.
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D3: The cancer does not respond to hormonal treatment, called hormone-refractory prostate cancer.
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D3.5: The cancer does not respond to the removal of the testes, called orchiectomy. Nor does it respond to LHRH analogs. But it does respond to other hormonal treatments.
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D4: The cancer does not respond to any kind of hormonal treatments or changes.