Diagnosing Prostate Cancer

Medically Reviewed by Nazia Q Bandukwala, DO on May 23, 2023
2 min read

Two initial tests are commonly used to look for prostate cancer in the absence of any symptoms. One is the digital rectal exam, in which a doctor feels the prostate through the rectum to find hard or lumpy areas known as nodules.

The other is a blood test used to detect a substance made by the prostate called "prostate-specific antigen" (PSA). When used together, these tests can detect abnormalities that might suggest prostate cancer.

Neither of these initial tests for prostate cancer is perfect. Many men with a mildly elevated PSA do not have prostate cancer, and men with prostate cancer may have normal levels of PSA. Also, the digital rectal exam does not detect all prostate cancers, as it can only assess the back portion of the prostate gland.

Other tests to check for prostate cancer may include:

Cystoscopy. This is also called a bladder scope. Your doctor uses a long, thin instrument called a cystoscope to peer into your urethra and bladder, an organ above your prostate that holds urine. The device has a tiny lens with light on one end and an eyepiece on the other.

Imaging tests. These make pictures of the insides of your body. Imaging tests used to detect prostate cancer may include:

  • Magnetic resonance imaging (MRI). Magnetic resonance imaging can give your doctor a closer look at any abnormal tumors in your prostate. A newer test called a multiparametric MRI produces higher-definition images.
  • Transrectal ultrasound (TRUS). This test relies on soundwaves to make a black and white image of your prostate. Your doctor inserts a thin probe through your bottom to pick up sound echoes.
  • Positron emission tomography (PET) scan. This is when your doctor injects a slightly radioactive material called a tracer into your bloodstream. The tracer shows up on a special camera to help flag cancer cells.
  • PSMA PET scan. This imaging technique also uses a radioactive tracer, but it can detect the spread of prostate cancer cells.
  • Bone scan. This can show if your prostate cancer has spread into your bones.
  • Computed tomography (CT) scan. This uses X-rays to take a picture. Your doctor may order a CT scan if your prostate cancer might have spread to your lymph nodes, or to other organs and structures in your body.

A definitive diagnosis for prostate cancer can only be confirmed by examining prostate cells under a microscope. This is done by performing a biopsy in a urologist's office. A small sample of tissue is taken from the prostate for testing and evaluation under a microscope.

Your doctor is likely to discuss your medical history with you. Answering questions about a history of prostate cancer in your family can help your doctor make an accurate diagnosis. Your doctor may also ask about any changes in your pattern of urinating.