The TNM staging system is used.

T (tumor size)

T 1 à The tumor is in the prostate, but due to its size it cannot be detected by a rectal exam though may be detected because of elevated PSA levels.

T 2 à The tumor is in the prostate, although in this case it can be felt during a rectal exam; there may be no symptoms

T 2a: The tumor is on half of one side or less (left or right) of the prostate.

T 2b: The tumor is found in more than half (left or right) of the prostate.

T 2c: The tumor is in the two lobes of the gland.

Tumors in stage T1 and T2 are known as "localized tumors."

T 3 à The tumoris located outside the prostate and may have involved the seminal vesicles or not.

T 3 a: T 3 The tumor is located outside the prostate, although there has been no involvement of the seminal vesicles.

T 3b: The tumor is located outside the prostate, and the seminal vesicles have become involved.

T4 à The tumor has spread into the urethra, rectum, bladder, or the pelvic wall.

Meanwhile, T3–T4 tumors are known as "advanced tumors" because in these stages the cancer has begun to invade nearby areas.

N refers to whether or not there are cancer cells in the nearby lymph nodes.

N Xà The nearby lymph nodes were not assessed.

N0 à The cancer has not spread into any of the lymph nodes.

N1 à The cancer has spread into one or more lymph nodes.

M indicates whether the cancer has spread to other parts of the body (metastatic). M0 if it hasn't spread, M1 if it has.

Grading

Once the tumor has been staged according to the TNM system, the Gleason scoring system is then used to grade the tumor.

Using the Gleason score and the level of PSA, the tumor is put into 4 categories ranging from I (the least advanced stage) to IV (the most advanced).

This determines the treatment options, likelihood of a cure, and prognosis.