The diagnosis of prostate cancer usually begins in your doctor’s office during a routine rectal exam followed by a blood test to measure prostate specific antigen (PSA). If your rectal exam shows abnormal changes or your PSA test is elevated, your doctor will need to do further testing to determine if you have cancer, benign prostatic hypertrophy, an infection, or some other condition.

Anatomy of the Prostate Gland

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Your doctor will ask about your medical history, including information about possible risk factors related to prostate cancer, and do a physical exam. Your doctor will also do testing to determine the nature of the abnormal cell growth of the prostate.

Tests may include the following:

  • Blood tests—Your doctor will take a blood sample to test for prostatic specific antigen (PSA). This is a chemical that indicates abnormalities in the prostate.
  • Transrectal ultrasonography (or ultrasound)—An ultrasound probe is placed into the rectum as close to the prostate as possible. The probe releases painless sound waves that bounce off the inner tissues of the prostate. The echoes produced by the sound waves create a picture on a computer screen that helps distinguish normal prostate tissue from cancerous tissue.
  • Transrectal biopsy —The biopsy sample is obtained by inserting a needle through the wall of the rectum into the prostate gland. Transrectal ultrasound is used to guide the doctor in placing the needle into the prostate. The area of the biopsy is usually numbed. This procedure typically takes 10-20 minutes and is performed in the doctor’s office.

Staging

If cancer is found in the biopsy sample, prognosis and treatment will primarily depend on:

  • Stage of the cancer
  • PSA value
  • Your general health

Staging is a careful attempt to determine the extent and seriousness of the cancer by taking into account the following factors:

  • Gleason score—a measure of the aggessiveness of the cancer as seen under the microscope
  • TNM staging system:
    • Tumor size and local spread (T)
    • Spread to lymph nodes in the area (N)
    • Spread or metastasis to distant organs (M)

In addition to a physical exam, tests used to stage prostate cancer include:

  • Urine and blood tests
  • Additional physical exam
  • X-ray —a test that uses radiation to take a picture of structures inside the body, including lungs, bladder, kidney, and lymph nodes
  • Bone scan —a nuclear medicine scan that uses radioactive material injected into your body to detect abnormal areas of bone. This is usually not done unless your PSA is above 10 ng/ml or you have bone pain.
  • CT or CAT scan —a type of x-ray that uses a computer to make pictures of structures inside the body
  • ProstaScint scan —a nuclear medicine scan that uses radioactive material injected into your body to detect prostate cells that may have traveled outside of the prostate. This study is still investigational and has not yet been proven to change disease management .
  • MRI scan —a test that uses magnetic waves to make pictures of structures inside the body
  • Lymph node biopsy —Tissue samples are taken from the lymph nodes surrounding the prostate and sent to the laboratory for examination.

Staging System

The TNM staging system is often used to classify cancer of the prostate. The Gleason score is often combined with the TNM system to predict the likelihood of survival over the next five years with treatment. The higher the numbers the worse the prognosis.

  • Tumor size and local spread (T):
    • T0: There is no evidence of tumor.
    • T1: The cancer is not felt during a rectal exam nor seen by ultrasound. It is usually found during treatment for benign prostatic hypertrophy or during evaluation of an elevated PSA test.
    • T2: The cancer can be felt during rectal exam, but is confined to the prostate.
    • T3: The cancer has spread just outside the prostate and may involve the seminal vesicles.
    • T4: The cancer has spread to local tissues beyond the prostate and seminal vesicles, organs, or lymph nodes.
  • Spread to lymph nodes (N):
    • N0: There is no evidence of cancer in any lymph node.
    • N1: Cancer has spread to one nearby lymph node that is <2 cm in size.
    • N2: Cancer has spread to one nearby lymph node 2-5 cm in size or multiple lymph nodes all <5 cm in size
    • N3: Cancer has spread to any nearby lymph nodes >5 cm in size.
  • Spread to distant organs (M):
    • M0: There is no evidence of distant spread.
    • M1: There is no distant spread to far removed lymph nodes, bones, or other organs.