03:18 PM Abstract No. 413 3-Tesla in-bore MR-guided biopsy: prostate cancer detection rate and clinical impact based on PIRADSv2

To evaluate the efficacy and clinical impact of 3 Tesla in-bore trans-rectal magnetic resonance-guided biopsy (3T MRGB) for prostate cancer (PCa) detection based on PIRADSv2 in patients with either suspected prostate cancer or under active surveillance. In this IRB-approved, HIPAA-compliant, retrospective study, 325 consecutive patients who underwent MRGB between February 2012 and July 2018 were evaluated. Twenty-six patients were excluded due to incomplete MRGB data. The final study cohort comprised 299 patients (mean age 68 years) divided into two subcohorts: those with no prior prostate cancer (NPCa) (n=182) and those under active surveillance (AS) (n=117). Prostate cancer detection rate, comparison with prior template trans-rectal ultrasound (TRUS)-guided biopsy and the percentage of clinically significant disease (CSD, defined as GS≥7) were evaluated in each subcohort. The detection rate was also correlated with preprocedural PIRADS (Prostate Imaging Reporting and Data System v2) score Mean interval time from pre-procedural MRI to 3T MRGB was 80 days with mean biopsy time of 55 minutes. Mean target sample per gland was 1.3. 3T MRGB detected PCa in 62.2% (186/299) of patients of whom 73.1% (136/186) had CSD. In 10 patients, MRGB detected high-grade intraepithelial neoplasia. No significant difference was seen in cancer detection rate between transitional (94/158) and peripheral zone (131/236) lesions (p > 0.5). 3T MRGB detected PCa in 55.5% (101/158) of patients in the NPCa subcohort, of whom 32 patients (31.7%) had prior negative TRUS-guided biopsy. In AS subcohort, 3T MRGB upgraded GS in 41% (48/117) of patients compared to GS on prior TRUS-guided biopsy. Overall, 3T MRGB altered clinical management in 26.7% (80/299) of patients. The overall and CSD detection rates for PIRADSv2 grades of 3, 4 and 5 were 26/78 (33.3%), 64/92 (69.9%), and 73/75 (97.3%); and 15/78 (19.2%), 46/92 (50%), and 59/75 (78.7%), respectively. The rate of urosepsis was 0.6% (2 cases). 3T MRGB was safe and yielded a high rate of overall and CSD detection rate of PCa in patients with suspected PC and those undergoing AS, altering clinical management in 26.7% of cases.