The value of magnetic resonance imaging-ultrasound fusion targeted biopsies for clinical decision making among patients with previously negative transrectal ultrasound biopsy and persistent prostate-specific antigen elevation

Abstract

Introduction: Targeted biopsy approaches have been shown to increase the detection of clinically significant prostate cancer (csPCa) within index prostate lesions. We report our initial experience with magnetic resonance imaging-ultrasound fusion biopsies (MRI-TB) in a population of men who had a previously negative transrectal ultrasound (TRUS) biopsy, persistent prostate-specific antigen (PSA) elevation, and ongoing suspicion of PCa. Patients were followed prospectively to assess for changes in clinical management following targeted biopsy. Methods: We prospectively followed the first 122 patients undergoing MRI-TB at our institution. All men had clinical suspicion of PCa, prior negative TRUS biopsies, and persistent PSA elevation. A total of 177 index lesions were identified on multiparametric MRI and reviewed using the prostate imaging reporting and data system (PI-RADS) V2 scoring system. Lesions classified as PI-RADS ≥3 received targeted biopsy. Biopsy-naive patients and those on active surveillance were excluded. The primary outcome was detection rate of csPCa, defined as International Society of Urological Pathology (ISUP) Grade Group (GG) ≥2. Multivariate analysis was used to determine predictors of csPCa on fusion biopsy. Results: Prior to fusion biopsy, patients had a mean of 17.9±8.6 negative core biopsies per patient and a median PSA of 9.5 (standard deviation [SD] 6.2) ng/nl. MRI-TB resulted in diagnosis of csPCa in 42/122 (34.4%) patients. Clinically significant PCa was found in eight (13.1%), 14 (21.9%), and 25 (48.1%) of PI-RADS 3, 4, and 5 lesions, respectively. The location of csPCa was within the peripheral zone (55.3%), transitional zone (40.4%), and central zone (8.5%). Clinical outcomes of patients with newly diagnosed csPCa show 4.8%, 57.1%, and 38.1% receiving active surveillance, radiation treatment, and radical prostatectomy, respectively. Predictors for csPCa were presence of PI-RADS 5 lesions, age, length of time from MRI to biopsy, and smaller prostate volumes. Conclusions: MRI-TB yields high detection rates for csPCa in men with elusive PSA elevation and frequently guides a change in clinical management. Clinical decision-making based on MRI findings and PI-RADS lesion scores are best informed by an understanding of institutional reporting patterns.