Effect of Biopsy Orientation on Prostate Cancer Detection Rates Using a Modified MRI-Fusion Biopsy Template
Jack Grinnan, MD1; Ilene Staff, PhD1; Joseph Tortora, MS1; Tara McLaughlin, PhD1; Sarah Valente, MD2; Joseph Wagner, MD1; Stuart Kesler, MD1
1Hartford Hospital, Hartford, CT; 2University of Connecticut Health Center, Farmington, CT
Introduction: The relative utility of axial (A) vs. sagittal (S) orientation of cores obtained through MRI fusion biopsy in the detection of clinically significant prostate cancer is a question of debate. Here, we sought to determine whether the two planes differ in the detection of 1) any cancer and 2) clinically significant cancer (CSC; defined as grade group 2 and above).
Materials and Methods: We retrospectively reviewed our prostate biopsy database to identify patients who had MRI-guided fusion biopsies from July 2016 to September 2017. We used a modified MRI fusion biopsy template in which 2 cores were taken in each of the A and S dimensions for one or more regions of interest (ROI) identified by the MRI; in addition, 12 cores were taken using traditional ultrasound guidance ("random" cores). We compared tumor detection rates for any cancer and for CSC for: A vs. S cores, A and S cores each vs. combined results and for MRI combined vs. random. For men with 2 ROIs, comparisons were made for each region and for a combined result. These comparisons were evaluated using the McNemar test. Differences between men with 1 or 2 ROIs were tested using chi-square tests of proportion. A p value of 0.05 was used to indicate significance for all tests.
Results: Biopsies for 268 men met inclusion criteria; 167 were positive and 101 were negative for any cancer. The median (IQR) age, PSA, and prostate volume was 64.5 years (53, 69), 5.81 ns/ml (4.3, 8.6), and 55 cc (40, 85). S cores were more likely than A cores to detect any cancer (35% vs.31%; p=.065); no differences were observed for CSC (15.3% vs. 14.9%). The combination of S and A was significantly better than either alone, with S and A cores missing 4.5% (p<.001), 9.0% (p<.001) of any cancers and 3.0% (p=.008), 3.4% (p=.004) of CSC, respectively. Random cores detected any cancer more often than MRI (60.8% vs. 39.6%, p<.001), but this was not true for CSC (p=.154). The detection rate for any cancer by A cores was significantly better among men with 2 ROIs vs. 1 ROI (41.6% vs. 27.4%, p=.035); no other associations were observed between detection rates, ROI and biopsy orientation.
Conclusions: Detection of both any cancer and CSC was better using a combination of A and S cores than it was using either plane alone, supporting the use of this modified template. This pattern was the only statistically significant finding related to CSC. S alone detected more cancer (but not more CSC) than A alone, but not when the MRI identified multiple ROIs. Cancer detection rates for MRI guided vs. random cores at this institution continue to be contrary to most published reports.
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