The necessity of dynamic contrast enhanced imaging for prostate MRI: A study of pathologic outcomes on prostate biopsy.

• DOI: 10.1200/jco.2017.35.6_suppl.52
• Publication Date: 2017-03-29T15:03:53Z
• Authors: Sasha C. Druskin; Jeffrey J. Tosoian; Allen Young; Kamyar Ghabili; Darian Andreas; Katarzyna Macura; Ashley Ross
• Keywords: 03 medical and health sciences; 0302 clinical medicine; 3. Good health

52 Background: PIRADS version 2 guidelines for the interpretation of multi-parametric prostate MRI (mpMRI) stipulates that dynamic contrast-enhanced (DCE) imaging be used to classify diffusion weighted imaging (DWI) score 3 peripheral zone lesions into PIRADS-3 (DCE-) or PIRADS-4 (DCE+) lesions. Despite this, it is unknown if DCE based classification separates lesions into clinically meaningful pathologic groups. Because use of contrast adds time, risk (though modest), and cost to mpMRI, we sought to examine whether use of DCE indeed improves detection of clinically-significant cancer. Methods: Using the Johns Hopkins MRI-ultrasound fusion prostate biopsy database and including only patients without a prior diagnosis of prostate cancer (n = 232), we identified patients with peripheral zone DWI-3 or DWI-4 lesions who underwent targeted biopsy of those lesions. Each lesion meeting the MRI criteria was considered separately, and grouped into one of three lesion MRI classifications – DWI-3/DCE-/PIRADS-3, DWI-3/DCE+/PIRADS-4, or DWI-4/PIRADS-4. The rates of benign, grade group (GG) 1, and GG ≥ 2 pathology were compared between the MRI classification groups. Results: One hundred forty-eight peripheral zone DWI-3 or DWI-4 lesions from a total of 106 patients were identified. The rate of benign(%)/GG1(%)/GG ≥ 2(%) biopsy pathology in the groups DWI-3/DCE-/PIRADS-3 (61 lesions), DWI-3/DCE+/PIRADS-4 (37 lesion), and DWI-4/PIRADS-4 (47 lesions) was 68.9/18.0/8.2, 59.5/13.5/18.9, and 44.7/23.4/27.7, respectively (P > 0.05 for the difference in rates of GG ≥ 2 pathology between the two PIRADS-4 groups and the two DWI-3 groups). Conclusions: Given the cost and morbidity of using intravenous contrast agents in prostate MRI, their clinical utility must be determined. In this study, DWI-3 peripheral zone lesions with DCE positivity appear to have a higher rate of clinically-significant (GG ≥ 2) cancer on biopsy. This study supports the use of DCE to better classify DWI-3 peripheral zone lesions however further study with expanded cohorts is indicated.