88 Background: Standard clinical and pathological parameters derived from diagnostic biopsy are insufficient to accurately assess final prostate tumor pathology of patients with biopsy Gleason grades 3+3 or 3+4. We developed a novel assay (ProMark) that performs quantitative measurements of 8 protein markers from prostate biopsy FFPE sections. In the validation study, assay risk scores were strongly predictive of final prostate tumor pathology with a C-stat of 0.69 (95%CI = 0.63 – 0.76) (p<0.0001). By design, the train-test (N=381) and validation (N=274) studies were enrichment studies, with a higher % of aggressive disease than in the intended use population. Here we study 293 needle biopsy cases that have come to our CLIA lab for ProMark testing over a four month period. The objective of this study is to establish the ProMark score distribution for these ‘real world’ clinical use patients, and to confirm that this distribution matches our clinical validation study. Methods: To establish prevalence of aggressive disease in the intended use population, we used the Institutional Urology Prostate Cancer Database at Johns Hopkins. Among 9,305 men with biopsy Gleason 3+3 or 3+4 and prostatectomy from 2004-2014 the distribution of favorable (GS<4+3 & organ confined) and unfavorable (GS≥4+3 or non-organ confined) based on surgical pathology is 73.1% vs. 26.9%. The adjusted risk score distribution from the validation trial (N=274) is then compared to the CLIA lab samples (N=293), based on cumulative distributions and binomial confidence intervals. Results: Comparison of the risk score distribution of early clinical data with the population-adjusted validation score distribution shows good agreement based on 95% CIs. Table shows expected and measured frequencies in Low, Intermediate and High risk categories. The K-S test for comparison of distributions has p-value=0.44, supporting equivalence of distribution. Conclusions: The results of our study show that early clinical practice closely matches expectations from controlled clinical studies. [Table: see text]
Can Prostatype® improve prognostic evaluation for metastasis and death in prostate cancer, a validation study
