The test is called a PCa3 test and stands for prostate cancer gene three. Prostate cells have PCA3 genes that make the cells produce a small amount of a particular kind of protein. Prostate cancer cells make much more of this protein than normal cells. PCa3 checks for the presence of the prostate cancer gene in your urine. For men who have an elevated PSA result, this test is used to help determine whether a biopsy should be done or whether you can just keep an eye on things for the moment. It measures something called the PCA3 mRNA (messenger RNA) and the PSA mRNA in a urine sample. Some reports have stated for up to 70 per cent of men with an elevated PSA, no cancer would be found in prostate tissue biopsy samples and these men are left to wonder if the elevated PSA is due to BPH or if the biopsy missed the cancer.
Cancer can be missed because the needles that are used to remove the tissue samples sometimes just miss the area of the prostate where the cancer is. Prostate biopsies are also not innocuous. A risk of infection does exist.
Although this risk is small, it can become life threatening in some men. There is data presently available from studies that show PCA3 may be more specific to prostate cancer than PSA, thus decreasing the likelihood of false positive biopsy results. For this test, you will be asked to drink about 500ml of water prior to the test.
This will then be followed by a digital rectal examination (DRE), yes, the mostly dreaded finger check. During the DRE, the left and right lobes of your prostate are stroked three times. This procedure is not painful and is usually done by a trained doctor or nurse.
Immediately following the DRE, you will be asked to provide about 20-30 cc of urine in a special container that is provided. This urine sample is then transferred to a special tube to be transported to the laboratory for analysis. The result of your PCa3 test is usually available in about a week to a week and a half.
A high PCA3 Score may indicate the need for a biopsy whereas a low PCA3 Score from a patient with an elevated PSA result may suggest that a relatively longer time interval may be acceptable before undergoing a biopsy.
The PCA3 and PSA mRNA measurements are combined to give you your PCA3 Score:
(PCA3 mRNA)/(PSA mRNA)x1000
A PCA3 Score cut-off of 35 yielded the greatest diagnostic accuracy for predicting the outcome of a biopsy.
The PCa3 test can be helpful if you are faced with the following:
• A negative prostate biopsy but there is still suspicion of prostate cancer
• You are being monitored with a diagnosis of early stage prostate cancer and want to know if the cancer is becoming more aggressive
• If you have a family history of prostate cancer and want to know if you should have a biopsy
If you and your doctor decide not to perform a prostate biopsy, the PCA3 test can be repeated after three-six months. If no prostate cancer is present, the PCA3 Score will generally remain the same or vary only slightly over time. The PCA3 test isn’t yet accurate enough to be used on its own as a test for prostate cancer. It is more likely to be used in addition to a PSA test.
For more information where you can get PCa3 testing, just send me an e-mail.