The validity of repeat prostate biopsy in prior biopsy negative patients: MRI-TRUS fusion guided biopsy

95 Background: To investigate validity of magnetic resonance imaging (MRI)-transrectal ultrasound fusion target biopsy (Fusion-Bx) compared with transrectal ultrasound-guided biopsy (TRUS-Bx) by evaluating detection rate of prostate cancer (PCa). Methods: Medical records of 376 patients with prior negative TRUS-Bx who underwent repeat prostate biopsy between Aug. 2015 and Apr. 2017 were retrospectively reviewed. The cohort was stratified into two groups (TRUS-Bx and Fusion-Bx) and clinical and biopsy characteristics patterns were analyzed. Conventional systemic randomized 12-core biopsy was performed in TRUS-Bx group whereas Fusion-Bx group applied additional 2-croes of target biopsy against suspicious lesions in MRI. Results: There were total 195 and 181 patients in TRUS-Bx and Fusion-Bx group, respectively. The overall cancer detection rate was slightly higher in Fusion-Bx group, but no statistical significance was observed (24.6% vs 28.7%, p = 0.367). Fusion-Bx group showed a significantly greater detection rate in target core analysis (5.0% vs 17.7%, p = 0.044). In confirmed positive biopsy patients, Fusion-Bx group had a higher rate of clinically significant prostate cancer (CsPCa) cases, but failed to achieve statistical significance (85.4% vs 92.3%, p = 0.271). When the patients with highly or very highly suspicious MRI (maximum image grade 4-5) findings in Fusion-Bx group was compared to the whole cohort of TRUS-Bx group, Fusion-Bx group was significantly greater in terms of overall detection rate (24.6% vs 38.0%, p = 0.017) and CsPCa detection rate (85.4% vs 97.0%, p = 0.009). Higher the target image grade, greater biopsy yield was achieved. Conclusions: For the patients who underwent repeat biopsy due to prior negative results, fusion-Bx showed better clinical significance including detection rate. A further study with a larger cohort size and prospective design is still needed to confirm the validity of Fusion-Bx.