The PCA3 test is a urine test. Researchers have been looking at whether they can use this test to diagnose prostate cancer.
While some results have been promising, some of the trials have produced different results. So it is still uncertain whether the PCA3 test can help to diagnose prostate cancer.
The PCA3 test is not used in standard practice in the NHS. It is available in a few private hospitals and clinics.
What PCA3 is
PCA3 is short for Prostate CAncer gene 3.
Prostate cells have PCA3 genes that make the cells produce a small amount of a particular protein. Prostate cancer cells make much more of this protein than normal cells.
When the level of PCA3 protein is high, it leaks into the urine.
How you have the PCA3 test
The test is in two parts. You have a rectal examination and then a urine test.
A rectal examination is where the doctor puts a gloved finger into the back passage (rectum). It is possible to feel the prostate gland by doing this.
You need to have a rectal examination because this massages the prostate gland and helps the PCA3 to go into the urine. You have to give the urine sample straight after the rectal examination. You normally get the results within a few days.
Diagnosing prostate cancer
At the moment, men with symptoms of prostate cancer have a number of tests to find out if they have cancer.
The tests include a PSA (prostate specific antigen) blood test and a rectal examination.
A PSA test is not a very accurate test for prostate cancer. Some men with a high level of PSA in the blood have prostate cancer. But some men who have prostate cancer have a low PSA level. And PSA levels can also be raised by several other medical conditions not related to cancer.
To examine your prostate gland, your doctor puts a gloved finger into your back passage (rectum). They check for abnormal signs, such as a lumpy, hard prostate.
Biopsy of the prostate gland
You might need more tests if you have a raised PSA and your prostate gland feels abnormal. Usually, this means a biopsy of the prostate gland.
Many men with raised levels of PSA who have biopsies don’t have cancer. Some men who continue to have raised PSA levels need to keep having biopsies. This isn’t very pleasant to go through and repeated biopsies can cause complications in some men.
To avoid having to do prostate biopsies, researchers have been trying to find a more specific test to show who has cancer and who doesn’t. One of the tests they have been looking at is the PCA3 urine test.
Research and NICE assessment
The PCA3 test was assessed by the National Institute for Health and Care Excellence (NICE) in 2015.
NICE don’t recommend the PCA3 urine in men who have already had an unclear or negative biopsy of their prostate gland. This is because the results of the trials so far have been mixed, with some showing the test was accurate but others not. NICE will review this decision if any new evidence becomes available.