Abstract C28: MRI/Ultrasound image fused guided TRUS prostate biopsy: Multiparametric MRI low suspicion lesions do not correlate with high-grade prostate cancer
Authors: Pinto Peter A. , Kruecker Jochen , Merino Maria , Linehan W. Marston , Turbey Ismail Baris , Choyke Peter , Wood Brad 
Published: May 2013

Introduction and Objectives: 3Telsa endorectal coil multiparametric magnetic resonance imaging (mpMRI) has been investigated as a new tool for physicians to improve prostate cancer detection. Depending on the number of MR sequences that are suggestive of cancer, MR lesions can be reported as having a low, moderate or high level of suspicion. Biopsy techniques to sample the MR lesions suspicious for cancer include in gantry platforms. While performing a prostate biopsy inside the MR gantry is challenging (long procedure times, expensive, not well tolerated by patients), platforms to perform office based MR / Ultrasound image fused TRUS biopsies have developed. While high suspicion lesions on MRI correlate strongly with the presence of cancer, the importance of low suspicion lesions has not been well characterized. We report the biopsy findings of patients with low suspicion lesions.

Methods: We reviewed all patients who underwent a 3 Tesla mpMRI of the prostate with endorectal coil from March 2007 to July 2011. Two radiologists independently reviewed and graded any suspicious lesions into low, moderate, or high risk groups. Lesions were stratified based on T2-weighted, spectroscopic, dynamic contrast enhanced (DCE) and diffusion weighted (DWI) MRI sequences. Low suspicion lesions are defined by a maximum of two positive parameters on mpMRI. Patients with only low suspicion lesions who subsequently underwent a random 12 core US biopsy + mpMRI/US fusion targeted biopsy were selected for and analyzed.

Results: Of 800 patients who received a mpMRI of the prostate, 92 patients (12%) had only low suspicion lesions on mpMRI. Mean age and PSA in this cohort were 59.7 years (36-81) and 7.84 ng/ml (0.3-64.7), respectively. All 92 patients underwent a mpMRI/US fusion biopsy plus a 12-core TRUS random biopsy. Sixty-two of these patients (67%) had no cancer detected. Of the remaining thirty patients (33%) who were diagnosed with cancer on biopsy, twenty-two patients had Gleason 6 disease and eight patients had Gleason 7 (3+4) disease. Ten patients went on to radical prostatectomy and no one was pathologically upgraded to high grade cancer. Thus, for low suspicion lesions, 90% had either Gleason 6 or no cancer on biopsy while 100% had no primary Gleason 4 on their biopsy.

Conclusions: Prostate MR imaging has improved considerably, as is true for many technology dependant medical devices. Currently 3T mpMRI of the prostate has become the most widely used imaging modality for lesion detection outside of ultrasound. As previously published, our image fusion biopsy platform allows for sampling of MRI suspicious areas. These results demonstrate that low suspicion lesions on mpMRI do not signify high grade cancer. This has implications not only for initial cancer detection and patient selection for treatment options, but may also obviate the need for annual biopsies in men on active surveillance. Larger cohort studies are required.

Citation Format: Peter A. Pinto, Jochen Kruecker, Maria Merino, W. Marston Linehan, Ismail Baris Turbey, Peter Choyke, Brad Wood. MRI/Ultrasound image fused guided TRUS prostate biopsy: Multiparametric MRI low suspicion lesions do not correlate with high-grade prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C28.