Disparities in baseline magnetic resonance imaging (MRI) utilization and imaging characteristics for prostate cancer (PCa) patients.

Abstract

119 Background: Blacks with low risk PCa more likely to have adverse pathologic features at prostatectomy and larger dominant intraprostatic lesions (DIPL) with high anterior foci prevalence. Whether pretreatment MRI identifies these differences is unknown. The aim of this study was to determine whether disparities exist in MRI utilization and imaging characteristics for PCa patients. Methods: An institutional database of 617 PCa patients treated with proton and/or intensity modulated radiotherapy from 2005-2013 identified patients with pelvic MRI (T2 weighted, diffusion weighted, and/or dynamic contrast-enhanced sequences, 91% with endorectal coil). DIPL presence, size, extracapsular extension (ECE) and seminal vesicle invasion (SVI) were reviewed. Whites vs. Blacks overall and stratified by risk group were compared using Fishers exact test for categorical and student’s t-test for continuous variables (P<0.05 significant). Results: Race was 367 White (59%), 208 Black (34%), and 42 Asian/Other (7%). Age (mean 67±8), Gleason score, and risk group did not differ significantly for Whites vs Blacks; clinical stage and mean PSA (ng/mL) did (White 8±11 vs Black 14±22, P<0.001). Overall, 472 (77%) patients underwent baseline MRI, with Blacks (67%) less likely than Whites (81%), P<0.001. The disparity was greatest for low-risk Blacks (47% vs 90%, P<0.001), not significant in the intermediate-risk group (70% vs 78%, P=0.205), and reversed in high-risk (94% vs 75%, P=0.007). There were no significant differences in DIPL presence, diameter, area, ECE, or SVI overall or within low- and intermediate-risk groups. For high-risk, Blacks demonstrated smaller DIPL in maximum diameter 17 ± 8 mm (vs 21 ± 10; P=0.042) and area 185 ± 156 mm2(vs 295 ± 285; P=0.042), with no differences in DIPL presence, additional IPLs, ECE, or SVI. Conclusions: In this urban, academic center cohort, Black PCa patients were significantly less likely to undergo staging MRI. No differences were found in DIPL presence, area, ECE, or SVI, except in the high-risk group. Further investigation is required to better understand how pretreatment MRI utilization and imaging characteristics differ by race.