Comparative Effectiveness of MRI-U/S Fusion versus In-bore MRI-targeted Prostate Biopsy
Francisco Ramos, BS1, Ruslan Korets, MD2, Aaron Fleishman, MPH2, Michael Johnson, MD2, Aria Olumi, MD2, Leo Tsai, MD, PhD2, Boris Gershman, MD2.
1Harvard Medical School, Boston, MA, USA, 2Beth Israel Deaconess Medical Center, Boston, MA, USA.
BACKGROUND: MRI-targeted biopsy has emerged as a standard of care in the management of men with elevated PSA and prostate cancer on active surveillance. Although two main biopsy techniques exist - MRI-ultrasound fusion (MRI-U/S) and in-bore MRI-targeted biopsy - the optimal MRI-targeted biopsy technique has not been established. We therefore examined the comparative effectiveness of MRI-U/S fusion biopsy performed in the office and in-bore MRI-targeted biopsy performed in Interventional Radiology.
METHODS: We identified men aged 18-89 with a diagnosis of elevated PSA or Gleason 6 prostate cancer on active surveillance who underwent MRI-U/S fusion prostate biopsy in the office or in-bore MRI-targeted biopsy performed in Interventional Radiology. MRI-U/S fusion biopsy comprised standard systematic (i.e., extended sextant) biopsies plus targeted biopsies, while in-bore MRI-targeted biopsy consisted only of targeted biopsies. The primary outcomes were cancer-detection rate (CDR; Gleason 6-10) and clinically-significant cancer detection rate (csCDR; Gleason 7-10). CDR and csCDR were compared across biopsy techniques using propensity-score adjustment for patient and MRI features using inverse probability of treatment weights (IPTW). In addition, the associations of biopsy technique with CDR and csCDR were evaluated, adjusted for patient and MRI features, using IPW-adjusted logistic regression.
RESULTS: A total of 169 patients were included in the study, of whom 49 (29.3%) underwent biopsy for Gleason 6 prostate cancer on active surveillance. Overall 93 patients underwent MRI-U/S fusion biopsy and 76 underwent in-bore MRI-targeted biopsy. Median patient age was 67 years (IQR 62-71), median pre-biopsy PSA was 7.2 ng/mL (IQR 5.2-10.2), and 29.7% of men were biopsy-naïve. Before adjustment, the CDR was 66% and 43% (p=0.014) for MRI-U/S and in-bore MRI biopsy, respectively, while the csCDR was 40% and 32% (p=0.27). After propensity score adjustment, baseline characteristics were well-balanced. After propensity score adjustment, there was no statistically significant difference in overall CDR (57% vs 55%; p=0.83) or csCDR (35% vs 37%; p=0.86) for MRI-U/S and in-bore MRI biopsy, respectively. Similarly, there was no statistically significant difference in CDR or csCDR when stratified by PI-RADS category (Table 1). In IPW-adjusted logistic regression, there was no statistically significant difference in CDR (OR 1.03; 95% CI 0.81-1.29) or csCDR (OR 0.98; 95% CI 0.80-1.20) for MRI-U/S fusion compared to in-bore MRI-targeted biopsy.
CONCLUSIONS: In this study, MRI-U/S fusion prostate biopsy and in-bore MRI-targeted prostate biopsy were associated with no statistically significant differences in CDR or csCDR overall or when stratified by PI-RADS score. Additional studies are required to determine if specific lesion characteristics may modify treatment effects. 
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