Introduction: While PSA screening has been instrumental in decreasing prostate cancer (PCa) mortality, it is also not a reliable test for identification of clinically significant Grade Group 2 (GG2) or higher disease. As such, solitary use of PSA for biopsy decision-making can lead to many unnecessary biopsies, over-detection of indolent cancer, or even missing aggressive cases. The ExoDx Prostate Intelliscore test is a non-invasive risk assessment biomarker tool that has been prospectively evaluated for detection of high grade prostate cancer and can help inform whether to proceed with biopsy. We aimed to evaluate the predictive utility for high-grade PCa of ExoDx and whether there is added value when combined with multi-parametric MRI (mpMRI) at our local institution. Methods: Records of 109 Medicare patients from University at Buffalo urology providers and affiliates who underwent urine ExoDx testing since 2021 were retrospectively reviewed. Most patients did receive mpMRI imaging and all did eventually proceed with systematic prostate biopsies. Those without a “gray-zone” PSA (2-10 ng/mL) and those with prior prostate biopsies were excluded. We analyzed the sensitivity (SE), specificity (SP), and negative and positive predictive values (NPV and PPV) of the ExoDx biomarker, mpMRI, PSAD, and ExoDx + mpMRI combination technique for detection of all prostate cancers and strictly high-grade prostate cancers (defined as Gleason grade 3+4 or higher). ExoDx Intelliscores >15.6, PIRADS 4 or 5 lesions on MRI, and PSAD’s > .15 were considered high prostate cancer risk values. Multivariate logistic regression modeling adjusting for age, PSA, prostate volume, and family history of PCa was then performed to examine each modality’s ability to predict biopsy-proven cancer. Statistical analysis was performed with SPSS with an a of 0.05. Results: 91 of the 109 patients enrolled met inclusion criteria. Mean age was 70.3 years, median PSA was 4.9. ExoDx had the highest sensitivity overall, but the lowest specificity (Table 1). A positive mRI had the highest specificity and positive predictive value for detecting high-grade prostate cancer between ExoDx and PSAD, though with significant sensitivity trade-off to ExoDx. Logistic regression modeling revealed that having a high ExoDx score or PIRADS 4/5 lesion on MRI were strongly associated with finding high-grade PCa (Table 2): ExoDx OR 6.52 (CI 2.87-15.8, p<.01), PIRADS 4/5 OR 13.41 (CI 3.19-41.22, p<.01), PSAD >.15 OR 2.12 (CI 0.63-4.31, p=.38).Combining the ExoDx biomarker with MRI resulted in the best predictive ability for detecting high-grade cancer with an OR of 18.67 (CI 4.54-68.1, p<.01). Conclusions: mpMRI outperformed both ExoDx and PSAD for detection of high-grade prostate cancer but with considerable trade-off in sensitivity to ExoDx. Incorporating the ExoDx biomarker with MRI resulted in the best predictive ability, suggesting there may be a synergistic detection effect with combination approach. This data suggests MRI alone may not be sufficient in certain cases and that employing the ExoDx test could provide added benefit for both biopsy decision-making and predictive capability. SOURCE OF Funding: N/A
