If you have received a prostate cancer diagnosis, your doctor will want to ascertain the grade (or Gleason score) and stage of your cancer. The grade and stage will determine treatment, which could include active surveillance. [Illustration: Dreamstime.com]

Illustration: Dreamtime.com

Prostate cancer is diagnosed by biopsying tissue from the prostate gland. If prostate cancer is suspected, your doctor will perform a biopsy guided by transrectal ultrasound. A small ultrasound probe is inserted into the rectum to guide the biopsy needle to the biopsy locations. The needle is inserted through the wall of the rectum into the prostate gland to retrieve small pieces of tissue. Typically, at least 12 samples of tissue are taken from different areas of the prostate. This can be done on an outpatient basis and is usually a brief procedure.

The tissue samples are sent to a pathology lab for examination. If cancer cells are seen they are often graded using a system called the Gleason score, which is an indicator of how likely the cancer is to spread. Tissue from two different parts of the prostate are examined and given a score from 1 to 5 and then the numbers from each part are added together to create the Gleason score. A lower score suggests a lower likelihood of spreading while a higher score suggests a greater chance.

Once a diagnosis of prostate cancer has been made, your doctor may request additional tests, which may include computed tomography (CT), magnetic resonance imaging (MRI), bone scan, positive emission tomography (PET), and/or lymph node biopsy. The goal of these tests will be to determine whether or not cancer has spread beyond the prostate. These test results, along with the Gleason score, will be used to stage the cancer.

The system most often used to define prostate cancer stages is the American Joint Committee on Cancer’s “TNM” system, which provides a Roman numeral staging score from I-IV, based on the size of the primary Tumor, whether or not there is lymph Node involvement, whether the tumor has Metastasized, the PSA level at diagnosis, and the Gleason score. The more advanced the cancer, the higher the TNM stage number.

Prostate Cancer Stages

Stage I Prostate Cancer: There are two scenarios that can be classified as Stage I.

• T1, N0, M0, Gleason = or <6, PSA <10: The cancer is localized to the prostate with no spread beyond the gland. Your doctor cannot feel the tumor by digital rectal exam (DRE) or visualize it by an imaging test.
• T2a, N0, M0, Gleason = or <6, PSA<10: The cancer is localized to the prostate with no spread beyond the gland. The tumor can be felt by DRE or visualized by an imaging test but is limited to half or less of one side of the gland.

Stage IIA Prostate Cancer: There are two scenarios that can be classified as Stage IIA.

• T1, N0, M0, Gleason = 7, PSA<20: The cancer is localized to the prostate with no spread beyond the gland. Your doctor cannot feel the tumor by DRE or visualize it by an imaging test.
• T1, N0, M0, Gleason = or <6, PSA = or >10 but <20: The cancer is localized to the prostate with no spread beyond the gland. Your doctor cannot feel the tumor by DRE or visualize it by an imaging test.

Stage IIB Prostate Cancer: There are three scenarios that can be classified as Stage IIB.

• T2c, N0, M0, and Gleason score, any PSA: The cancer is localized to the prostate with no spread beyond the gland. The tumor can be felt by DRE or visualized by an imaging test and is in both sides of the gland.
• T1 or T2, N0, M0, any Gleason score, PSA = or >20: The cancer is localized to the prostate with no spread beyond the gland. The tumor may or may not be felt by DRE or visualized by an imaging test.
• T1 or T2, N0, M0, Gleason = or >8, any PSA: The cancer is localized to the prostate with no spread beyond the gland. The tumor may or may not be felt by DRE or visualized by an imaging test.

Stage III Prostate Cancer

• T3, N0, M0, any Gleason score, any PSA: The cancer has grown outside the prostate and may have grown into the seminal vesicles but has not spread to lymph nodes or other places in the body.

Stage IV Prostate Cancer

• T4, N0, M0, any Gleason score, any PSA: The cancer has not spread to lymph nodes or distant locations in the body but has spread to nearby tissues (aside from the seminal vesicles) such as rectum, bladder, pelvic wall, or urethral sphincter.
• Any T, N1, M0, any Gleason score, any PSA: The cancer may or may not have spread to nearby tissues and has spread to nearby lymph nodes. The cancer has not spread to distant locations in the body.
• Any T, any N, M1, any Gleason score, any PSA: The cancer may or may not have spread to nearby tissues and/or lymph nodes. The cancer has spread to distant locations in the body.