In-Bore Versus Fusion MRI-Targeted Prostate Biopsy of PI-RADS Category 4 or 5 Lesions: A Retrospective Comparative Analysis Using Propensity Score Weighting.

Abstract

Background: Few published studies have compared in-bore and fusion MRI-targeted prostate biopsy, with conflicting results. Objective: To compare the target-specific cancer detection rate of in-bore versus fusion MRI-targeted biopsy. Methods: We retrospectively identified men who underwent in-bore or fusion MRI-targeted biopsy of PI-RADS category 4 or 5 lesions between August 2013 and September 2019. PI-RADS version 2.1 score, size, and location of each target were established by retrospective review by a single experienced radiologist. Patient history and target biopsy results were obtained by electronic medical record review. Only the first MRI-targeted biopsy of the dominant lesion was included for patients with repeated biopsies or multiple targets. Inbore and fusion biopsy were compared using propensity score weights and multivariable regression to adjust for imbalances in patient and target characteristics between biopsy techniques. The primary endpoint was target-specific prostate cancer detection rate. Secondary endpoints included detection rates after applying propensity score weighting for International Society of Urologic Pathology (ISUP) Grade Group (GG) 2 and above cancer, as well as when including off-target systematic sampling results. Results: The study sample included 286 men (191 and 95 men who underwent in-bore and fusion biopsy, respectively). In-bore biopsy had a significantly higher likelihood of detecting any cancer (odds ratio = 2.28, 95% CI 1.04 - 4.98; p=.04), and a non-significantly higher likelihood of detecting ISUP GG2 or above cancer (odds ratio = 1.57, 95% CI 0.88 - 2.79; p = .12), in a target compared to fusion biopsy. When including off-target sampling, in-bore biopsy and combined fusion and systematic biopsy were not different for detection of any cancer (odds ratio = 1.16, 95% CI 0.54 - 2.45; p = .71) or ISUP GG2 and above cancer (odds ratio = 1.15, 95% CI 0.66 - 2.01; p = .62). Conclusion: In this retrospective study using propensity score weighting, in-bore MRI-targeted prostate biopsy had higher target-specific cancer detection rate compared to fusion biopsy. Clinical impact: Pending a larger prospective randomized multicenter comparison between in-bore and fusion biopsy, in-bore may be the preferred approach should performing only biopsy of a suspicious target, without concurrent systematic biopsy, be considered clinically appropriate.