The PCA3 is a gene-based urine test that helps to diagnose prostate cancer. It works by collecting a urine sample after a digital rectal exam, and sending it out for analysis. This analysis will yield a PCA3 score. Unlike the PSA blood test, PCA3 is specific for prostate cancer and is not affected by prostate enlargement or other non-cancerous prostate conditions.
When used in conjunction with a PSA test and DRE, the additional information can help a doctor decide if a biopsy is needed or can be delayed. Alternatively, if you have a positive biopsy, the PCA3 score may give additional information about the aggressiveness of the cancer helping you to decide which treatment option is best for you.
When should you use a PCA3 test?
Because this test gives you more information, you should use it if you have an elevated PSA or a suspicious digital rectal exam. This extra piece of information can help you decide whether or not to have a biopsy. It can also be used if you have had a negative prostate biopsy but there is still suspicion for prostate cancer, or if you have a family history of prostate cancer.
If you’ve had a positive biopsy then a PCA3 score will give you more information regarding the aggressiveness of the cancer. Similarly, if you are on active surveillance, the urine test can give you information on how the cancer is progressing.
The PCA3 Score indicates the probability of finding prostate cancer in a biopsy. This means the higher the PCA3 Score, the more likely the biopsy will be positive, and vice versa. In the absence of prostate cancer the PCA3 score will remain the same or vary only slightly over time, but if the PCA3 score increases a biopsy may be suggested.
In terms of the treatment of prostate cancer, a high score will give you an idea of how aggressive the cancer is and if definitive treatment, like surgery or radiation, is necessary or in your best interest. If you have early stage, non-aggressive cancer then PCA3 can be used in your surveillance treatment to spot changes in the cancer’s behavior. If there is a big increase, this may mean the cancer is changing and progressing. Overall, if you have a positive biopsy, the PCA3 score may give additional information about the aggressiveness of the cancer and may help in deciding which treatment is appropriate.