Purpose: The 18-gene MyProstateScore 2.0 (MPS2) test was previously validated for detection of Grade Group≥2 (GG≥2) prostate cancer using post-digital rectal examination (DRE) urine. To improve ease of testing, we validated MPS2 using first-catch, non-DRE urine.
Materials and methods: Patients provided first-catch urine prior to biopsy. MPS2 values were calculated using previously-validated models differing only by extent of clinical data included: biomarkers alone (BA; no clinical data), biomarkers and clinical factors (BA+CF), and biomarkers, clinical factors, and prostate volume (BA+CF+PV). The primary outcome was GG≥2 cancer on biopsy. MPS2 performance and clinical consequences of testing were compared to PSA and the Prostate Cancer Prevention Trial risk calculator (PCPTrc).
Results: The cohort included 266 men with median PSA 6.6 ng/mL (IQR 4.9-9.1), of which 103 (39%) had GG≥2 cancer on biopsy. The area under the curve for GG≥2 cancer was 57% for PSA, 62% for PCPTrc, and 71%, 74%, and 77% for MPS2 models. Under a testing approach detecting >90% of GG≥2 cancers, MPS2 testing would have avoided 36-42% of unnecessary biopsies, as compared to 13% using the PCPTrc. In patients with a prior negative biopsy, MPS2 testing would have avoided 44-53% of repeat biopsies, as compared to only 2.6% using PCPTrc.
Conclusions: Using first-catch urine, MPS2 meaningfully improved the proportion of biopsies avoided relative to PCPTrc while maintaining highly-sensitive detection of GG≥2 cancer. Non-DRE testing provides a convenient, objective, and highly-accurate testing option to reduce the need for imaging and biopsy in men with elevated PSA.
Keywords: biomarkers; early detection of cancer; liquid biopsy; prostate cancer.