Staging the disease of prostate cancer

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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 and instead take more of a ‘watchful waiting’ approach also known as active surveillance.  But 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 is a way to describe how much cancer is in your body and where it is located in the body.

Staging of prostate cancer gives the doctor the information he needs to know on how big the tumor is, whether it has spread or not and if it has spread, where has the cancer gone to. 

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.

·      PSA blood test is used primarily to screen for prostate cancer and 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 is an indication of a more advanced cancer.  The doctor will want to know how fast the PSA levels have been rising from test to test as 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 from this 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, it suggests the cancer is slow growing and not aggressive.  A higher number indicates a faster growing cancer that is likely to spread.

 

·      Imaging tests used to determine prostate cancer can include CT scans, MRI, or a bone scan.

How prostate cancer is staged and what they mean

All cancers have a staging system which is 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 5 key pieces of information:

1. The extent of the main (primary) tumor (T category)

2. Whether the cancer has spread to nearby lymph nodes (N category)

3. Whether the cancer has spread (metastasized) to other parts of the body (M category)

4. The PSA level at the time of diagnosis

5. The Gleason score, based on the prostate biopsy (or surgery)

·      Stage I cancer

This stage is known as localized cancer as 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 a slow growing cancer.

·      Stage II cancer

This stage of cancer is still localized and has not spread beyond the prostate 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 – found only on one side of the prostate

·      Stage IIB – found in both sides of the prostate

·      Stage III cancer

This stage of cancer is called locally advanced prostate cancer and has spread outside the prostate into local tissue such as the seminal vesicles, the glands that make semen. 

·      Stage IV cancer

This stage of 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 such as the bladder, liver, or lungs. 

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.  Men diagnosed with stage IV prostate cancer, the goal is to improve symptoms and to prolong life as in most cases, stage IV prostate cancer is not curable.

Depending on the stage of prostate cancer along with the PSA and Gleason score, will help the doctor to decide on the best treatment taking into account a man’s:

·      Age

·      Overall health

·      Symptoms

·      Side effects of treatment

·      What chance the treatment can cure the cancer