Introduction: The miR Sentinel® Test measures the expression of 442 small non-coding RNAs (sncRNAs) extracted from urinary exosomes to differentiate patients with no molecular evidence of prostate cancer (NMEPCa) from those with molecular evidence of prostate cancer (MEPCa). The test further classifies men with MEPCa into low-, intermediate- or high-risk disease. We compared the results of the miR Sentinel® PCC4 Test to systematic and magnetic resonance imaging (MRI)-guided core needle biopsy in men at risk for prostate cancer undergoing biopsy.

Methods: A total of 763 biopsy-naive men over 45 years of age undergoing systematic and/or targeted biopsy were recruited. sncRNAs were isolated from urinary exosomes and interrogated by RT-qPCR on a custom-designed OpenArray platform.

Results: The molecular classification was compared to the biopsy grade group (Table 1). Sensitivity for NPEPC or grade group (GG) 1 vs. GG 2–5 was (75+18+4+105=203)/221=92.2% and the negative predictive value for absence of GG 2–5 PCa was  (221+64+12+123=420)/(238+200=420)=96%. The apparent false-positive rate for GG 2–5 cancer was (34+35+32+22=(123)/(543)=23%. A total of 208  patients had discordant systematic and targeted biopsies; 29 of these had a negative systematic biopsy and a positive targeted biopsy. The molecular test predicted the targeted biopsy outcome in 27/29=93.1% overall, and in 14/15 (93%) of the cases with GG 2–5 cancer. In the 18 patients with positive systematic and negative MRI-targeted biopsies, the test result predicted the positive biopsy in 100%. 

Conclusions: The miR Sentinel Test offers an accurate, non-invasive means to accurately identify the presence or absence of prostate cancer and classify risk status to predict pathological grade on biopsy. The high predictive accuracy of the test in patients whose systematic and targeted biopsies were discordant suggests that the 23% discordance between the negative biopsy result and the positive Sentinel Test result was, in most cases, due to false-negative biopsies.