PD38-05 MAGNETIC RESONANCE IMAGING/ULTRASOUND FUSION-GUIDED BIOPSY DETECTS CLINICALLY SIGNIFICANT PROSTATE CANCER IN THE CENTRAL GLAND CORRELATING WITH INDEX LESION

INTRODUCTION AND OBJECTIVES: Central gland (CG) prostatic adenocarcinomas (CaP) are historically reported with lesser incidence, smaller tumor volume, and higher Gleason scores when compared to the peripheral zone (PZ). Additionally, index tumor lesions as defined by highest grade may be missed when residing in the CG. MRI/US fusion-guided biopsy allows targeting of lesions seen on MRI, potentially better identifying cancer outside the traditional TRUS biopsy template. METHODS: Retrospective review was performed of 1003 patients who underwent MR/US fusion-guided biopsy of 2119 suspicious lesions. Targets were stratified by zonal distribution of the lesion on multiparametric MRI (mpMRI) in the CG or PZ. Detection rates for Gleason 4þ3 cancers were tabulated by location and correlated with PSA, Gleason score, prostate volume and MRI suspicion. RESULTS: MR/US fusion-guided biopsy targeted lesions in the central (n1⁄4711, 34%) or peripheral (n1⁄41408, 66%) prostatic zones. Cancer detection rate was similar between zonal distributions, 35.2% in the CG compared to 33.6% in the PZ (p1⁄40.497) (Table 1). Cancer detection of clinically significant disease (Gleason 4þ3) was found to be similar in the CG and PZ (11.4% vs 11%, p1⁄40.128) despite a higher prostate volume in those with CG lesions (p1⁄4 0.004). In contrast to random 12-core TRUS biopsy, upgrading occurred in 18.5% of patients with CG lesions versus 13.3% for PZ targets (p1⁄40.024). When MRI detected suspicious lesions in the CG, 36.6% (77/210) of these represented the highest risk lesion. These CG index lesions translated to 13% (77/592) of the entire cohort of men with biopsy-proven CaP. CONCLUSIONS: Prostate cancer of the central gland occurs at a similar frequency than in peripheral zone. Targeted lesions of the CG were more likely to be upgraded from 12-core biopsy, frequently representing the index lesion as determined by Gleason grade. In all patients upgraded by a CG lesion, CG targeted cores constituted the highest Gleason grade index lesion in a third of all males with prostate cancer. Multiparametric MRI and fusion-guided biopsy aids in identifying clinically significant disease of the CG not captured on traditional TRUS biopsy. Source of Funding: This research was supported by the Intramural Research Program of the National Institutes of Health (NIH), National Cancer Institute, Center for Cancer Research, and the Center for Interventional Oncology. NIH and Philips Healthcare have a cooperative research and development agreement. NIH and Philips share intellectual property in the field.