MP28-04\u2003CORRELATION BETWEEN MRI PHENOTYPES AND A GENOMIC CLASSIFIER OF PROSTATE CANCER

Abstract

INTRODUCTION AND OBJECTIVES: We sought to evaluate the correlation between MRI phenotypes of prostate cancer as defined by the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) and Decipher Genomic Classifier (used to estimate the risk of early metastases). METHODS: This single-center, retrospective study included 72 men with prostate cancer who underwent 3T MRI before radical prostatectomy performed between April 2014 and August 2017 and whose lesions were microdissected from radical prostatectomy specimens and then tested with Decipher (89 lesions; 23 MRI invisible [PI-RADS v2 scores ⩽ 2] and 66 MRI visible [PI-RADS v2 scores ≥ 3]). Linear regression analysis was used to assess clinicopathologic and MRI predictors of Decipher results; correlation coefficients (r) were used to quantify these associations. Area under the receiver operating characteristic curve (AUC) was used to determine whether PI-RADS v2 could accurately distinguish between low-risk and intermediate-/high-risk lesions (cutoff Decipher score, 0.45). RESULTS: Median age was 63 years (range: 42-76), and median PSA was 9.8 ng/mL (range: 1.2-69). The lesions’ grade groups (GG) were GG1=8, GG2=40, GG3=18, GG4=5, GG5=18. MRI-visible lesions had higher Decipher scores than MRI-invisible lesions (mean difference 0.22; 95% CI 0.13, 0.32; p < 0.0001); most MRI-invisible lesions (82.6%) were low risk. PI-RADS v2 had moderate correlation with Decipher (r = 0.54) and had higher accuracy to distinguish between low-risk and intermediate-/high-risk lesions (AUC 0.863) than prostate cancer grade groups (AUC 0.780) in peripheral zone lesions (95% CI for difference 0.01, 0.15; p = 0.018). CONCLUSIONS: MRI phenotypes of prostate cancer are positively correlated with Decipher risk groups. Although PI-RADS v2 can accurately distinguish between lesions classified by Decipher as low or intermediate/high risk, some MRI-invisible lesions have the potential for aggressive behavior. Figure. No caption available. Source of Funding: Philips/Radiological Society North America Research and Education Foundation Seed Grant and Cleveland Clinic Center for Clinical Genomics