Magnetic Resonance Imaging–Ultrasound Fusion Biopsy During Prostate Cancer Active Surveillance

Abstract

BackgroundFusion biopsy using multiparametric magnetic resonance imaging (MRI) and transrectal ultrasound has demonstrated favorable detection rates of high-grade prostate cancer (PCa) among previously undiagnosed men. However, the diagnostic yield among men with active surveillance (AS) remains undefined. ObjectiveTo determine the utility of MRI-ultrasound fusion biopsy during AS by reporting rates of PCa upgrading and comparing findings with systematic biopsy. Design, setting, and participantsWe identified patients with low- and intermediate-risk PCa enrolled in AS who received MRI-ultrasound fusion surveillance biopsies. All completed prostate multiparametric MRI with 3-T and endorectal coil reviewed by radiologists selecting regions of interest, and all underwent MRI-ultrasound fusion biopsy with concurrent systematic biopsy. Outcome measurements and statistical analysisWe report MRI-ultrasound fusion biopsy findings, rates of Gleason score (GS) upgrading to ≥3 + 4 (any upgrading) and to ≥4 + 3 (major upgrading), tumor involvement estimates using descriptive statistics, McNemar's test of symmetry, and multivariate logistic regression. Results and limitationsOverall, 207 men underwent MRI-ultrasound fusion biopsy following radiologic suspicion on multiparametric MRI and met inclusion criteria. Agreement between systematic and MRI-ultrasound fusion biopsy GS was borderline statistically significant (p<0.047). In total, 83 men (40%) experienced any upgrading, including 49 (24%) on systematic sampling, 30 (14%) on MRI-targeted cores, and four (2%) on both. Among those with negative results on MRI-ultrasound fusion biopsy, seven (9%) exhibited major upgrading with systematic biopsy. MRI suspicion scores were high (4/5) for all but two patients with any upgrading and for all who experienced major upgrading. On multivariate analysis, older age was associated with higher odds of any upgrading for men with GS ≤3 + 3 on previous biopsy (odds ratio: 1.10; 95% confidence interval, 1.01–1.20; p=0.03). ConclusionsMRI-ultrasound fusion biopsy resulted in upgrading otherwise undetected by systematic biopsy among a proportion of men with PCa managed with AS. However, upgrading also occurred in areas outside targeted biopsy, suggesting that systematic sampling should be offered to men with AS even with history of extended sextant biopsy. Patient summaryThis study examined the role of magnetic resonance imaging (MRI)–ultrasound fusion biopsy for men with prostate cancer managed with active surveillance (AS). In some patients, MRI-ultrasound fusion biopsy resulted in the detection of upgrade otherwise missed with systematic sampling. The findings indicate that MRI-ultrasound fusion biopsy may help with better sampling during AS.