MP77-18 OUTCOMES OF MRI-US FUSION TARGETED PROSTATE BIOPSY IN MEN WITH HISTORY OF PROSTATIC INTRAEPITHELIAL NEOPLASIA AND/OR ATYPICAL SMALL ACINAR PROLIFERATION: EVIDENCE FOR AN ALTERATION OF CURRENT PRACTICE.

INTRODUCTION AND OBJECTIVES: While PCA3 has been shown to be predictive of prostate cancer (CaP) detection in the setting of systematic biopsy (SB), performance in the setting of targeted MRI-ultrasound fusion biopsy (MRF-TB) is not well described. METHODS: Biopsy results in all men undergoing both SB and MRF-TB, using the Artemis/Pro fuse system, between June 2012 and June 2014 were reviewed. PCA3 scores, highest MRI suspicion score (mSS), and cancer detection rates were extracted from 143 patients without a previous cancer diagnosis. Receiver operating characteristics (ROC) were analyzed to determine the performance of PCA3 in predicting cancer on MRF-TB at varying thresholds. In bivariable analyses, the association between elevated PCA3 and MRF-TB findings were analyzed. The predictive capability of PCA3þmSS was compared to that of mSS alone by fitting multivariable logistic regression models and comparing ROC and areas under the curve (AUC). RESULTS: Table 1 summarizes the predictive capability for Gleason 3þ3 or higher disease on MRF-TB, stratified by threshold. In bivariable analyses using a threshold of 35, a greater proportion of those with a high PCA3 demonstrated cancer on MRF-TB than those with a low PCA3 (46.8% vs. 18.8%, p < 0.001). Similarly, patients with a high PCA3 and mSS 3 were more likely to have cancer on MRF-TB than those with a low PCA3 and mSS 3 (48.8% vs. 26.7%, p 1⁄4 0.004). In multivariable analyses, a logistic regression model containing both PCA3 and mSS was associated with significantly higher discrimination of cancer on MRF-TB compared to a model of mSS alone (AUC 0.786 vs. 0.741, p 1⁄4 0.038). Potential study cohort outcomes by threshold are detailed in Table 2 CONCLUSIONS: The predictive capability of PCA3 for prostate cancer is retained in the setting of MRF-TB. Addition of PCA3 to mSS would improve the overall diagnostic accuracy of MRF-TB, but further work is needed to determine the impact of PCA3 at individual thresholds.