Diagnosis of Prostate Cancer

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

© 2008 Nucleus Medical Art, Inc.

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. Another blood test often drawn is the prostatic acid phosphatase (PAP), but this test is much less sensitive for the diagnosis of prostate cancer than is the PSA.

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 takes about 30 minutes and is performed in the doctor’s office.


If cancer is found in the biopsy sample, prognosis and treatment depend on the aggressiveness, called Gleason’s score, size, PSA value, and stage of the cancer, as well as your general health.

Staging is a careful attempt to determine whether the cancer has spread and, if it has, what body parts are affected. Additional tests to determine staging may include:

  • Urine and blood tests
  • Additional physical exam
  • X-rays of various parts of 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 proven to change management of your disease.
  • 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.
  • Laparoscopy – A laparoscope is inserted through a small cut near the navel. This small, telescope-like device is about the width of a pencil and has a light on one end and a magnifying lens on the other. This helps your doctor examine the internal abdominal organs.

Staging System

The following staging system is used to classify cancer of the prostate:

Stage I : 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. This stage has three levels (Ia, Ib, or Ic) depending on how the cancer is found.

Stage II : The cancer can be felt during rectal exam but is confined to the prostate. This stage has two levels, IIa or IIb, depending on whether the cancer is on one side of the prostate or both sides.

Stage III : The cancer involves tissue beyond the prostate. This stage has two levels, IIIa or IIIb, depending on whether the cancer involves the seminal vesicles.

Stage IV : The cancer has spread to other organs or lymph nodes.

Further Staging

The letters N and M are also used to help classify cancers that have spread to lymph nodes and distant organs:

N0 : The cancer has not spread to any lymph nodes

N1 : The cancer has spread to local lymph nodes

M0 : The cancer has not spread to distant organs or lymph nodes

M1 : The cancer has spread to distant organs or lymph nodes


American Cancer Society website. Available at: http://www.cancer.org .

National Cancer Institute website. Available at: http://www.cancer.gov .

Last reviewed February 2007 by Barbara Harty-Golder, MD, JD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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