Diagnosing The Different Stages Of Prostate Cancer

Cancers, including prostate cancer, can be staged in a variety of ways. Staging is the process through which a doctor determines how far the cancer may have spread. 

Staging uses a variety of clinical and pathological tests performed by your doctor. 

Not every exam is necessary in every case. It depends on the findings of your biopsy, which is a test that looks for cancer in tissue from your prostate gland.

The following tests can help determine the stage of prostate cancer:

Digital Rectal Exam

The Digital Rectal Exam (DRE) is a physical exam that your doctor will perform to detect abnormalities in your prostate. The DRE is also used to determine the stage of your cancer and monitor the effectiveness of your treatment. 

During this test, the doctor looks for abnormalities in the gland's form, consistency, or thickness.

Prostate-Specific Antigen (PSA) Test

PSA is a protein found in greater concentrations in the prostate when there is a medical issue or illness. 

PSA levels in the blood usually are pretty low but can grow in some circumstances, including sexual stimulation or illnesses like prostate cancer.

A PSA blood test is used to screen for prostate cancer. If PSA levels are elevated, your doctor may advise further testing. 

The DRE and PSA are often performed together.

Gleason Score

The Gleason Score helps determine the aggressiveness of prostate cancer¹. Your doctor can use this grading system to select the best treatment choices.

The Gleason grading system is a two-number system in which the first number is assigned to the predominant focus of the tumor and the second to the secondary predominant pattern. Both are graded on a scale of one-five.

Generally, the cut-off for prostate cancer starts with a Gleason Score of 3+3 cancer.

Grade Groups

Grade Groups are a novel method of evaluating prostate cancer that addresses some of the shortcomings of the Gleason grading system. 

The International Society of Urological Pathology (ISUP) modified the Gleason grading system to a five-grade system. Grade group one encompasses Gleason 3+3 disease. Gleason 3+4 is layered into a different grade than Gleason 4+3.

Although the Grade Group system may ultimately replace the Gleason system, the two systems are now used simultaneously.

Stage grouping

The TNM system, developed by the American Joint Committee on Cancer², is the most frequently used cancer staging method, classifying cancer from stage one through stage four. The current revision of the AJCC system uses both the Gleason Score and the grade group for staging.

The method uses three distinct features of tumor development and spread:

• Tumor(T): What is the size of the primary prostate cancer area?

• Nodes(N): Is it spreading to the lymph nodes? If so, how far and how many? 

• Metastasis(M): How far has prostate cancer spread?

The cancer stage will assist both you and your doctor in determining the best treatment choices. 

Your doctor will combine your T, N, and M results with the Gleason score and PSA level in a process called stage grouping.

Stage I

Stage I prostate cancer indicates that the tumor occupies up to 50% of one side of the prostate. Cancers in the first stage generally develop slowly.

• The cancer is developing in your prostate but has not gone beyond it. 

• In most situations, imaging tests do not reveal anything to the doctor. 

• The Gleason Score is less than six.

• The PSA level is less than ten.

Stage II

The tumor remains limited to your prostate and has not spread to your lymph nodes or other parts of your body. The doctor may or may not feel the tumor during a DRE or see it on an imaging test.

This stage is divided into three sub-stages:

Stage 2A:

• Cancer has spread to one or both sides of the prostate gland.

• The PSA level in the blood is between ten and 19.

• The Gleason Score is six or less.

Stage 2B:

• Cancer has spread to one or both sides of the prostate gland. 

• The Gleason Score is seven. 

• The PSA level in the blood is less than 20.

Stage 2C:

• Cancer has spread to one or both sides of the prostate gland. 

• The PSA level in the blood is less than 20.

•  The Gleason Score is between seven and eight.

Stage III

Stage III indicates that the cancer has spread locally. With a high Gleason Score and PSA level, the tumor has advanced and is more likely to develop and spread. 

This stage is divided into three sub-stages:

Stage 3A:

• Cancer has spread to one or both sides of the prostate.

• The PSA level in the blood is 20 or higher.

• The Gleason Score can reach eight.

Stage 3B:

• Cancer has progressed outside the prostate gland but not to the lymph nodes. 

• The PSA might be at any level.

• The Gleason Score can be as high as eight.

Stage 3C:

• Similar to stage 3B, the disease may not spread beyond the prostate.

• The Gleason Score is nine or ten.

Stage IV

Stage IV prostate cancer has progressed to the lymph nodes or other areas of the body. It is subdivided into two stages:

Stage 4A:

• Cancer has progressed to adjacent lymph nodes but has not migrated to surrounding tissues.

Stage 4B:

• Cancer has progressed to another body part, such as the bones or distant lymph nodes - otherwise known as metastatic disease.

Survival rates

The 5-year relative survival rate for prostate cancer is 98%. That indicates life expectancy is approximately the same as that of the general population.

If prostate cancer has progressed to other parts of your body, such as your lungs, liver, or bones, the five-year relative survival rate is 30%³. 

The survival rate does not indicate how long you will live. It can, however, offer you an idea of how likely it is your treatment will be successful.

Treatment

Effective treatment for prostate cancer is generally possible, especially if it is detected early. If testing reveals that you have prostate cancer, your doctor will discuss treatment options with you.

The prostate cancer stage must be correctly identified since it determines which treatment is most appropriate.

Learn more about the most common treatments for prostate cancer, including surgery and active surveillance.