Tests to Detect Prostate Cancer

Prostate cancer is usually found through the following methods:

• Physical exam of your prostate through the rectum with a gloved finger
• Prostate-specific antigen (PSA) blood test
• Magnetic resonance imaging (MRI) of the prostate
• Prostate biopsy

During a prostate biopsy, a fine needle is used to remove small samples from the prostate gland for microscopic examination to determine if there are cancer cells. The transrectal ultrasound-guided prostate biopsy is the conventional method to obtain tissue for definitive confirmation of a diagnosis of cancer.

However, the transperineal technique is fast replacing the transrectal route as the new standard due to proven lower rates of infection and potentially higher rates of accuracy. The primary goal for your doctor at this stage is to correctly identify if you have prostate cancer, and if so, to determine exactly how aggressive and how extensive it is. This will help guide your treatment plan for prostate cancer.

The prostate biopsy is an invasive procedure and is not without risks of complications. This can include pain, blood in your urine, infection and temporary difficulty in passing urine.

There may also still be a chance of false negative results (e.g. the biopsy fails to identify cancer when there is cancer) or misjudgment of your cancer’s aggressiveness. This can occur if some critical areas of your prostate are missed during the biopsy, also known as undergrading of the tumor due to sampling error.

Learn more: Your Prostate Biopsy: What to Expect

However, there are other tests available to further inform you of your prostate cancer risk and guide your decision on whether you should undergo a prostate biopsy.

The PSA blood test remains the foundation of prostate cancer detection, with higher PSA levels suggesting an increased risk of prostate cancer. However, it remains imperfect as a tumor marker as the test cannot differentiate between benign conditions of the prostate such as an inflamed prostate and prostate cancer.

Learn more: The PSA Test: What to Expect

A physical examination of your prostate by your doctor will help identify any abnormal growths. Discovering these at this stage, may suggest that a biopsy would be a good idea for you. Unfortunately, the bedside prostate examination with a gloved finger is not very reliable, and support from imaging techniques greatly help improve the accuracy of your diagnosis.

If you are being considered for a prostate biopsy either due to elevated PSA levels or an abnormal prostate examination, imaging of the prostate (e.g. MRI) can help determine if you need it, and if so, identify where the cancer is most likely to be present. This information helps guide the prostate biopsy process and increases its accuracy.

In addition, an MRI of the prostate also helps determine the extent of the spread of the prostate cancer, specifically if the cancer has extended beyond the confines of the prostate gland and into surrounding regions in the pelvis such as lymph nodes. This information helps guide treatment decisions for your prostate cancer. Computed tomography (CT) and bone scans can also be used to assess the spread of cancer to other parts of the body beyond the pelvis.

Learn more: An Introduction to Prostate Cancer Scans

Due to the challenges that remain in prostate cancer diagnosis, other new tests are being studied to improve the accuracy and safety of testing for prostate cancer:

• Alternative blood-based tests

Other blood tests for prostate cancer include the Prostate health index (Phi) and the four kallikrein (4K) score tests. They have been recently approved by the US Food and Drug Administration (FDA), and help to predict how likely you are to face aggressive prostate cancer before confirming if you should do a biopsy. They do this by detecting specific target proteins in your blood, the kallikreins. Optimistically, both tests have been estimated to enable around a quarter of men to avoid an unnecessary biopsy.

• Urine-based tests

Urine tests for prostate cancer risk include the ExoDx, SelectMDx and Mi-Prostate Score. Similar to blood-based tests, they are designed to help to predict how likely you are to face aggressive prostate cancer before your doctor confirms if you should do a biopsy. They work by detecting pieces of your genetic material found in your urine that are associated with prostate cancer.

Learn more: Prostate Cancer Biomarkers

While resources available at your hospital may differ, if you are offered one of these new tests, they will provide a more accurate and personalized assessment of your prostate cancer risk and how aggressive it may be. This will help you and your doctor decide whether you should go through with a prostate biopsy.

Finally, despite the wide availability of screening tests for prostate cancer, the final confirmation of prostate cancer still depends on a prostate biopsy to detect the presence of cancer cells.