In nearly 1,000 men undergoing initial or repeat biopsy, these investigators found that urinary PCA3 prior to a prostate biopsy improved the prediction of PCa and high-grade disease with a high positive predictive value 90% in the initial biopsy setting and a high negative predictive value 88% in the repeat biopsy setting. The investigators conclude that counseling men undergoing prostate biopsy in the context of PCA3 would reduce the burden of prostate biopsies.
via Prostate Cancer Screening: Moving Beyond PSA – Renal and Urology News.
I have been using PCA-3 tests in a variety of ways. I perform it yearly for men at high risk of prostate cancer, to determine if men need repeat prostate biopsies, and also in my active surveillance prostate cancer patients.
“Over-expression of the PCA3 gene is highly specific to cancerous prostate tissue,” John Wei, MD, MS, Professor of Urology at the University of Michigan Health System in Ann Arbor, said in a company-issued statement. “When evaluated with other risk factors, the PROGENSA PCA3 assay fills an important unmet clinical need by helping physicians identify which men suspected of having prostate cancer should undergo a repeat prostate biopsy.”
via PCA3 Test Okayed to Help Decide Need for Repeat Prostate Biopsy – Renal and Urology News.
I’ve been using the PCA-3 test for a few years. I have used it for this indication, as well as for patients who opt for active surveillance for their prostate cancer. I am glad the test was approved for this use by the FDA.
MedWire News: Prostate cancer patients urinary prostate cancer antigen 3 PCA3 scores are strongly indicative of tumor volume, and could be a useful marker of suitability for treatment with active surveillance AS, study findings show.
via MedWire News – Oncology – PCA3 predicts prostate tumor volume and could indicate AS suitability.
I have been using PCA3 tests to estimate tumor burden for men choosing active surveillance for about 2 years. I also check a PCA3 test after some time for men on active surveillance. The values that are considered to be significant will need to be studied.
May 12, 2008 — The urine test for the PCA3 gene, already marketed for use in diagnosing prostate cancer, could also be useful in prognostication. It might have clinical application in selecting men with low-grade and low-volume tumors who would be suitable candidates for active surveillance, say researchers writing in the May issue of the Journal of Urology.
The PCA3 urine test, marketed in Europe by Gen-Probe, has been shown in previous studies to be more accurate in diagnosing early prostate cancer than serum levels of prostate-specific antigen (PSA).
I usually use the PCA 3 test for men who have had a negative biopsy and we are considering performing a second one. I usualy use it for men with high grade PIN after one biopsy. If the PCA 3 is positive, I usually perform a second biopsy. I have not looked at my data to see if the above correlation exists, but that would be interesting.
I also am not sure if you can use PCA 3 tests that are taken a few months apart to mean anything. For example, would a rise in PCA 3 be expected if a man develops cancer or the cancer is growing?
There is a new company that is using the PCA3 gene that has obtained approval in Europe. In the US there are 2 companies that have the test, Ameripath and Bostwick laboratories, currently the PCA3-plus test.
We have had a lengthy discussion about this test on another blog entry on my site.
The test works by looking at the ratio of this PCA3 RNA to the total PSA RNA that is expected to be constant.
The idea is that a higher ratio means that you are more likely to have cancer. I have found several cancers using this test as my basis for performing a prostate biopsy.
One interesting development is the change in Bostwick’s interpretation of the result. Ameripath always used 35 as the “normal” cutoff, and Bostwick started at 10. Bostwick has increased the normal value of the test to 35 now.