PCA3 test in patients with suspected prostate cancer

Frequently asked questions on the topic of PCA3

Can the PCA3-Test for patients with suspected prostate cancer be used as a decision-making aid for biopsy even if the patient has previously been diagnosed with prostatitis?
The Prostate CAncer Gene 3 (PCA3) test may be used as an indication for a prostate biopsy when there are suspicions of prostate cancer; i.e. if there are abnormal digital-rectal examination findings or if the prostate-specific antigen (PSA) value is in the range of 2.5-10 ng/ml.

An increase in the PSA value may have a variety of causes, such as inflammation of the prostate (prostatitis), benign prostatic hyperplasia or prostate cancer. PSA is indeed prostate-specific, but not prostate cancer-specific! PCA3, on the other hand, is truly prostate cancer-specific (since it is only produced by prostate cancer cells). Neither prostate size nor prostate inflammation plays a role.

The PCA3 test can give additional information before a biopsy is performed – even if the patient previously had or still has prostatitis. A high PCA3 Score makes a positive biopsy result statistically more likely, while a low score is associated with a reduced risk of malignant disease.

Can the PCA3 test be used to assess the progress of a therapy or a relapse after systemic or local prostate cancer therapy?
Following prostate cancer therapy, the prostate-specific antigen (PSA) test remains the best available tumour marker for assessing therapeutic success and the possible recurrence of a tumour. Regular PSA checks during after-care make it possible to detect a recurrence, and this helps with the decision of whether additional therapy is necessary.

The Prostate CAncer Gene 3 (PCA3) test is not a replacement for the PSA test. This test is an additional marker that can be used to help a man who has suspected prostate cancer to decide whether a prostate biopsy is really necessary.

According to the latest publications, the PCA3 test can also be used in patients under „active surveillance”.

In contrast to this, there is no data yet on the use of the PCA3 test for checking therapy (e.g. after a total surgical procedure, radiation [EBRT], high-Intensity focused ultrasound [HIFU] or systemic therapy such as hormone withdrawal or chemotherapy).

Is the PCA3 test affected by a urinary tract infection?
There is still no information on whether or not the Prostate CAncer Gene 3 (PCA3) test might be affected by a urinary tract infection. There are as yet no clinical indications for this either.

Can the PCA3 score be used in the context of an „active surveillance strategy”?
To date, the Prostate CAncer Gene 3 (PCA3) test has primarily undergone scientific study as a decision-making aid with regard to (re-)biopsy.

The test indicates the probability that prostate cancer would be found in the course of a biopsy. When the PCA3 score is high, there is also a high probability of finding cancer. In such cases, a biopsy would be urgently advised.

Preliminary study results indicate that the PCA3 score also permits conclusions to be drawn regarding the aggressiveness of the cancer. This could then also help in choosing appropriate therapy – for example, whether to maintain a strategy of „active surveillance” or change to another form of therapy. The higher the PCA3 score, the higher the probability that the tumour has reached a size that might be dangerous for the patient (in such cases, we speak of a clinically significant tumour). This needs to be confirmed accordingly through another biopsy. These preliminary results are updated by further scientific tests.
5-alpha reductase inhibitors, such as dutasteride or finasteride, reduce the prostate volume and lower the prostate-specific antigen (PSA) value.

Do these substances also affect the PCA3 score?

To date, there is no evidence that dutasteride or finasteride has any influence on the value of the Prostate CAncer Gene 3 (PCA3) score in the diagnosis of prostate cancer. Nor is this to be expected. Both of these substances work by blocking the 5-alpha reductase enzyme, which converts testosterone to dihydrotestosterone. This leads to a shrinking of the prostate, followed by a decrease in the prostate-specific antigen (PSA) value, which correlates with the size of the prostate. In contrast with the PSA value, the PCA3 score does not depend on the size of the prostate. It is therefore unlikely that the PCA3 score will be affected by taking dutasteride or finasteride, as long as there is no prostate cancer. However, it must be borne in mind that PCA3 is specifically produced by prostate cancer cells. If dutasteride or finasteride influence these cells in any way, this could also have an effect on the PCA3 score. Further investigations are necessary.


Source
www.PCA3.org

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