INTRODUCTION AND OBJECTIVE:
Genomic tests have been proposed as supplements to assess need for prostate biopsy. The present study seeks to assess the cumulative predictive value of patient demographics, PSA velocity, and genomic tests (OPKO4K, SelectMDx™, and ExoDX) in predicting positive biopsy.
From April 2007 to December 2019, 359 men presented to a single center with an elevated PSA and had an OPKO4K test ordered to assess PC risk. Out of 359, 113 men had ExoDx tests ordered. Abnormal tests were defined as an OPKO4K score ≥7.5% and ExoDx IntelliScore≥15.6. Four receiver-operator characteristic (ROC) curves were generated to assess predictive capability for a positive biopsy: (1) baseline characteristics of age, baseline PSA, and digital rectal exam, (2) model 1 + OPKO4K score ≥7.5%, and (3) model 2 + ExoDx IntelliScore≥15.6, and (4) model 3 + MRI. Logistic regression models were used to calculate the added value of each test.
Of the 359 men, mean±SD average age was 65.0±8.7 years and mean baseline PSA was 7.1±6.1ng/ml. Of those tested, 272 (75.7%) men were found to be high-risk for PC, of which 161 (59.2%) proceeded to prostate biopsy. Positive biopsies were found in 84/161 (52.2%).The sensitivity, specificity, positive predictive value, and negative predictive value for OPKO4K were 86.7%, 69.6%, 52.1%, and 72.3%, respectively. Figure 1 depicts the four models, each with increasing predictive capability: (1) baseline characteristics of age, baseline PSA, and digital rectal exam (AUC=0.535), (2) model 1 + OPKO4K score ≥7.5% (AUC=0.653), and (3) model 2 + ExoDx IntelliScore≥15.6 (AUC=0.766), and (4) model 3 + MRI (AUC=0.825). Overall, the addition of OPKO4K and ExoDX scores to baseline characteristics significantly increased predictive capability. Adding MRI with biomarkers yielded a high predictive capability of 0.825.
In combination with traditional factors like age and baseline PSA, the stepwise addition of OPKO4K combined with ExoDx test significantly improves decision for the need of prostate biopsy. Incorporation of both tests prior to MRI provides outstanding discrimination between men with a low versus high probability of positive prostate biopsy. Utilizing MRI with combination of biomarkers has high predictive capability in men with elevated PSA.
Source of Funding: