Diagnosing Prostate Cancer

Prostate cancer biopsy

A biopsy is a procedure that can be used to diagnose prostate cancer. A biopsy is when a small piece of tissue is removed from the prostate and looked at under a microscope to see if there are cancer cells.

A biopsy is the main tool for diagnosing prostate cancer, but a doctor can use other tools to help make sure the biopsy is made in the right place. For example, doctors may use transrectal ultrasound or magnetic resonance imaging (MRI) to help guide the biopsy. With transrectal ultrasound, a probe the size of a finger is inserted into the rectum and high-energy sound waves (ultrasound) are bounced off the prostate to create a picture of the prostate called a sonogram. MRI uses magnets and radio waves to produce images on a computer. MRI does not use any radiation.

Gleason score

If cancer is found in the biopsy tissue, the pathologist gives the cancer a grade. The grade describes how different the cancer cells look from normal prostate cells under a microscope. The grade also indicates how likely the cancer is to grow and spread. This grade is called the Gleason score.

The Gleason score can range from 6 to 10. The higher the Gleason score, the more likely the cancer will grow and spread quickly.

Prostate cancer staging

If prostate cancer is diagnosed, other tests are done to find out if cancer cells have spread within the prostate or to other parts of the body. This process is called staging. Whether the cancer is only in the prostate or has spread outside the prostate (metastatic cancer) determines your stage of prostate cancer. The stage of prostate cancer tells doctors what kind of treatment you need. The results from a prostate-specific antigen (PSA) test, the Gleason score, and imaging studies are used to stage prostate cancer.

More information

• Prostate Cancer Treatment (PDQ®)–Patient Version (National Cancer Institute)
• Stages of Prostate Cancer (National Cancer Institute)