The complexity of prostate cancer makes it slightly different from other forms of cancer. Some men who are diagnosed with this disease may not need any treatment. Instead, they take a “watchful waiting” approach also known as active surveillance. However, other men may require more immediate intervention depending on how advanced the cancer is at the time of diagnosis. Any diagnosis of cancer will have its own method of staging of the cancer detected. Cancer staging describes how much cancer is in the body and where it is located.
Staging of prostate cancer gives the doctor the information he needs to know about how big the tumor is, whether it has spread or not, and if it has spread, where. Staging is necessary for several reasons:
- It helps the doctor decide the best way to treat the cancer
- It can determine the chance of recovery or prognosis
- It can help find clinical trials a person might be able to join
Testing for Prostate Cancer
When a man is diagnosed with prostate cancer, the initial staging is based on the results of PSA blood tests, biopsies, and imaging tests. This phase of staging is referred to as clinical staging.
A PSA blood test is used primarily to screen for prostate cancer. It measures the amount of prostate specific antigen (PSA) in the blood. PSA is a protein produced by both cancerous and noncancerous tissue in the prostate gland. The higher the level of PSA, the more advanced the cancer. The doctor will want to know how fast the PSA levels have been rising from test to test because a faster increase could indicate a more aggressive tumor.
A biopsy of the prostate can be done in the doctor’s office, and the results can tell what percent of the prostate is involved. It can also determine a Gleason score, which is a number from 2 to 10 showing how closely the cancer cells look like normal cells when viewed under a microscope. If the score is less than 6, the cancer is growing slowly. If the score is higher, the cancer is more aggressive.
Imaging tests used to determine prostate cancer can include CT scans, MRI or a bone scan.
How Prostate Cancer Is Staged
All cancers have a staging system, or a standard way for the oncologist to describe how advanced the cancer is. For prostate cancer, the most widely used staging system is the American Joint Committee on Cancer (AJCC) TNM system.
The TNM system for prostate cancer is based on five key pieces of information:
- The extent of the main (primary) tumor (T category)
- Whether the cancer has spread to nearby lymph nodes (N category)
- Whether the cancer has metastasized to other parts of the body (M category)
- The PSA level at the time of diagnosis
- The Gleason score, which is based on the prostate biopsy (or surgery)
Stage I cancer
This stage is known as localized cancer because the cancer has been found in only one part of the prostate. Stage I cancers cannot be felt during a digital rectal exam or seen with imaging tests. If the PSA is less than 10 and the Gleason score is 6 or less, stage I cancer is most likely slow growing.
Stage II cancer
This stage of cancer is still localized but is more advanced than stage I. In stage II, the cells are less normal than stage I and may grow more rapidly. There are two types of stage II prostate cancer: Stage IIA means that the cancer is found only on one side of the prostate, whereas Stage IIB means that the cancer is found in both sides of the prostate.
Stage III cancer
This stage of cancer is called locally advanced prostate cancer. It means the cancer has spread outside the prostate into local tissue such as the seminal vesicles, the glands that make semen.
Stage IV cancer
In this stage, the cancer has spread to distant parts of the body, such as nearby lymph nodes or bones of the pelvis or spine. It could have spread to other organs as well, such as the bladder, liver or lungs.
For men diagnosed with stage I, II or III prostate cancer, the goal is to cure the cancer by treating it and keeping it from returning. F men diagnosed with stage IV prostate cancer, the goal is to improve symptoms and to prolong life. In most cases, stage IV prostate cancer is incurable.
Determining the stage of prostate cancer along with the PSA and Gleason score will help the doctor decide on the best treatment.
Patients newly diagnosed with prostate cancer can contact world renowned prostate cancer surgeon and urologic oncologist, Dr. David Samadi. For a consultation and to learn more about prostate cancer risk, call 212-365-5000.