Questions and Answers
Does the PCA3 Score only help in deciding whether a biopsy is needed or can it also aid in differentiating significant (aggressive) from insignificant (indolent) cancer?
The PCA3 test provides additional information which can help you and your doctor decide if a biopsy is needed or can be delayed (see also PCA3 background information). Other factors such as your age, prostate size, prostate specific antigen (PSA) level and the outcome of the digital rectal examination (DRE) are also considered in this decision.
The PCA3 Score, which is the outcome of the PCA3 test, indicates the probability of finding prostate cancer in the biopsy: the higher the PCA3 Score, the more likely that cancer will be found in the biopsy (i.e. a positive biopsy). This indicates that a biopsy can be recommended if your PCA3 Score is high or can be delayed/avoided if your PCA3 Score is low (see also How should the PCA3 Score be interpreted?).
Recent studies indicate that the PCA3 Score may also differentiate between significant/aggressive and non-significant/indolent cancer (see also PCA3 background information and PCA3 Utility). If cancer is found in the biopsy, the PCA3 Score may give additional information about the significance/aggressiveness of the cancer. This can aid in the decision on treatment, e.g. if active treatment like surgery or radiotherapy is needed or if active surveillance (monitoring potential cancer progression by means of DRE, PSA and/or PCA3) is an alternative. The higher the PCA3 Score, the higher the probability that the cancer is significant/aggressive.
When comparing clinical studies, it appears that the median PCA3 Score was around 20 in men with ‘indolent’ prostate cancer and around 50 in men with ‘significant’ prostate cancer. It can thus be suggested that if cancer is found in the biopsy, a PCA3 Score < 20 is likely to indicate that this is indolent prostate cancer and that active surveillance may be a valid (first) treatment option . In the decision which therapy is most appropriate, other factors that give an indication on cancer significance should also be taken into consideration, e.g. the Gleason score found in the biopsy specimen, and the tumour volume.
1. van Poppel H, et al. The relationship between PCA3 and prostate cancer significance. BJU Int 2011;109:360-6