Should I discuss referral for an imaging procedure such as magnetic resonance imaging (MRI) or the conduct of a diagnostic biomarker test?
Imaging (such as MRI) and biomarkers (such as SelectMDx) give different information about your prostate, which is often complementary. Imaging provides an anatomical picture of your prostate, while biomarkers provide biological information of your prostate cells.
An MRI procedure is non-invasive, safe and covered by most health insurance because it is already available for several years. Unfortunately, not all clinical centres have MRI machines available so travel time can be long. In addition, waiting lists are often long and not all persons are fit to undergo an MRI procedure. For example if you have non-MRI compatible implants, allergies to the contrast agent, or claustrophobia. Also, the interpretation of MRI images requires specialists (uro-radiologists) with real expertise in this domain. An MRI image may still leave you with a certain risk of having aggressive prostate cancer .
SelectMDx is a biomarker-based urine test that combines the expression levels of two genes in a urine sample with traditional clinical risk factors of an individual patient to determine the likelihood of finding (aggressive) prostate cancer upon biopsy. This test has a 2% risk of missing aggressive prostate cancer (negative predictive value, NPV 98%). This means that if the test is negative, you can be 98% sure that you do not have aggressive prostate cancer and can thus avoid an unnecessary biopsy.
There is also the possibility of using biomarkers such as SelectMDx and MRI in sequence. The SelectMDx test can first be performed to determine the likelihood of having prostate cancer. If the likelihood is high, there is a high risk of having prostate cancer but the exact location is not known. This is where MRI can help: it can determine where the suspicious lesions are located and help in guiding the biopsy. The biopsy should be performed to determine the aggressiveness of the cancer and determine the appropriate treatment.
If the SelectMDx is demonstrating a very low risk for aggressive prostate cancer, you can rule out with 98% certainty that there are aggressive prostate cancer cells present in the prostate. This will allow you and your physician to make the most informed choice about undergoing, delaying, or avoiding a prostate biopsy.
Read more about your options when you have an elevated PSA.
- Moldovan PC, Van den Broeck T, Sylvester R, et al. What Is the Negative Predictive Value of Multiparametric Magnetic Resonance Imaging in Excluding Prostate Cancer at Biopsy? A Systematic Review and Meta-analysis from the European Association of Urology Prostate Cancer Guidelines Panel. Eur Urol 2017;72:250-66