After a prostate cancer diagnosis, your oncologist will research the stage of your disease. Prostate cancer staging is crucial for planning the best treatment.
A diagnosis of prostate cancer is anything but rare. In fact, about one in five American men will have prostate cancer sometime in their life, most often in their later years, according to the National Cancer Institute.
After tests and a physical exam suggest a man may have cancer of the prostate (a small gland that sits below the bladder in men), a biopsy is performed. If malignant cells are found, confirming the diagnosis, the next step in preparing for treatment is prostate cancer staging.
Why prostate cancer staging is important for successful treatment
The staging of prostate cancer is based on tests to find out how much cancer is in the body and how serious the cancer is. Oncologists stage prostate cancer according to the size of the tumor, whether the malignancy is likely to metastasize (spread to other parts of the body) or has already metastasized when diagnosed and several other factors.
This information is compiled to give a man’s prostate cancer a specific designation in stages I through IV. However, prostate cancer staging also involves many sub-categories based on specific findings about the tumor. This kind of detailed information is crucial so cancer specialists can zero in on the best treatment for prostate cancer.
In some cases where the cancer is slow growing and in an early stage — depending on the man’s age, health and preferences — no treatment other than "watchful waiting" may be indicated. Other men with very aggressive cancer in more advanced stages may need surgery and several forms of treatment for the best prognosis possible.
Prostate cancer staging is complex
The system cancer specialists use most often for prostate cancer staging, according to the American Cancer Society (ACS), is the American Joint Committee on Cancer’s TNM system, which stands for tumor, nodes, and metastasis.
- The TNM system is based on these key facts about a man’s prostate tumor:
- The size of the main (primary) tumor
- Whether or not the malignancy has spread to nearby lymph nodes
- Whether the cancer has metastasized to other parts of the body
- The level of prostate-specific antigen (PSA) — a protein made in the prostate — when the cancer was diagnosed.
- The Grade Group, a measurement of how likely the cancer is to grow and metastasize quickly, based on the Gleason score (a system that assigns a grade between 1 and 5 to indicate how abnormal prostate cells appeared on biopsy)
An overview of prostate cancer stages
Prostate cancer stages are labeled I through IV. The lower the number, the less the cancer has spread, if at all, while a higher number means the malignancy has metastasized, the National Cancer Institute explains. There are also sub-categories and various letters and numbers indicating a host of additional information to help your oncologist plan the best treatment.
Here’s an overview of the basics of prostate cancer stages:
- Stage I prostate cancer covers cancer found only in the prostate that can’t be felt during a digital rectal exam and is discovered by needle biopsy performed for an elevated PSA test or in a sample of tissue removed during surgery for other reasons. However, Stage I also includes cancer felt during a digital rectal exam but only found in one-half or less of one side of the prostate. In either case, the PSA level is less than 10 and the Grade Group is 1, indicating the cancerous cells look much like normal cells.
- Stage II prostate cancer is more advanced than stage I but has not spread outside the prostate. It’s divided into three different sub-stages. In Stage IIA, cancer is found in one-half or less of one side of the prostate or both sides; the PSA level is less than 20 and the Grade Group is 1. Stages IIB and IIC prostate cancers are much the same as Stage IIA, except the Grade Group is 2 for Stage IIB and 3 or 4 for Stage IIC, indicating more abnormal looking cells were found in biopsies.
- Stage III prostate cancer is divided into three categories. The IIIA stage means cancer is found on one or both sides of the prostate and PSA levels are 20 are higher; the Grade Group, indicating how abnormal the biopsied cancer cells appeared, can range from 1 to 4. Stage IIIB indicates cancer has spread to nearby tissue or organs and the PSA and Grade Group can be any level. Stage IIIC means cancer is in one or both sides of the prostate and may have spread to nearby areas and the PSA is 20 or over. What distinguishes IIC is the Grade Group ranking of 5, indicating more aggressive malignant cells have been found on biopsy.
- Stage IV prostate cancer has two sub-categories. Stage IVA indicates the disease is in one or both sides of the prostate, and may have spread to nearby tissues and organs but has definitely already spread to lymph nodes near the prostate gland. The PSA and Grade Group may be any level. Stage IVB means the cancer has spread from the prostate to other parts of the body, including bones and distant lymph nodes.
If you or someone you know is diagnosed with prostate cancer, understanding exactly what a specific prostate cancer stage means can be confusing. So, don’t hesitate to talk to your doctor and go over anything you are confused about and ask questions you need answered.
September 22, 2020
Janet O’Dell, RN