How is prostate cancer detected?

The most effective means of detecting prostate cancer early is through a screening, which involves a digital rectal exam and measuring the amount of prostate-specific antigen (PSA) in the blood. In a digital rectal exam, the doctor inserts a gloved, lubricated finger into the anus in order to feel the shape and size of the prostate.

The PSA test is believed to find most prostate cancers. PSA is a protein that the prostate secretes into the bloodstream. If a man has higher levels of this antigen, it may mean he has prostate cancer.

If cancer is suspected, the doctor will perform a prostate biopsy (removal of tiny pieces of prostate tissue). By removing a tissue sample from the tumor and examining it, doctors can confirm or rule out a diagnosis of cancer and determine whether the disease has spread to other organs.

What if prostate cancer is diagnosed?

Fortunately, most prostate cancers have not spread at the time they are diagnosed, and the cancer is most often limited to the prostate gland.

To help predict how aggressive the prostate cancer is, your physician will look at your PSA levels before the biopsy, and will also calculate the “Gleason Score.” The Gleason Score is a sum of the grades of the two most common prostate tumors.

After looking at tiny sections of the prostate tissue biopsy through a microscope, the pathologist assigns a grade from 1 to 5 to the tumors, based on their appearance (with 1 being closest to normal appearance and 5 being least normal). The Gleason Score can range from 6 to 10, with 6 being the least aggressive form of cancer (confined to the gland) and 10 the most aggressive form (highest risk of spreading outside the gland).

From the PSA levels and the Gleason Score, a treatment plan is created. For men with a low risk of the cancer spreading outside the gland, staging studies such as bone scans and computed tomography scans are not needed. Men who have cancer with a higher likelihood of spreading may need these staging studies to learn where the cancer may have spread.

Last reviewed by a Cleveland Clinic medical professional on 07/24/2015.


  • National Cancer Institute. Prostate cancer—for patients Accessed 4/16/18.
  • American Cancer Society. Prostate cancer Accessed 4/16/18.
  • Corn P, Logothetis C. Chapter 34. Prostate Cancer. In: Kantarjian HM, Wolff RA, Koller CA. eds. The MD Anderson Manual of Medical Oncology, 2e. New York, NY: McGraw-Hill; 2011.

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