Prostate cancer diagnosis: multiparametric MR-targeted biopsy with cognitive and transrectal US-MR fusion guidance versus systematic biopsy--prospective multicenter study.

PURPOSE: To compare biopsy performance of two approaches for multiparametric magnetic resonance (MR)-targeted biopsy (TB) with that of extended systematic biopsy (SB) in prostate cancer (PCa) detection.

MATERIALS AND METHODS: This institutional review board-approved multicenter prospective study (May 2009 to January 2011) included 95 patients with informed consent who were suspected of having PCa, with a suspicious abnormality (target) at prebiopsy MR. Patients underwent 12-core SB and four-core TB with transrectal ultrasonographic (US) guidance, with two cores aimed visually (cognitive TB [TB-COG]) and two cores aimed using transrectal US-MR fusion software (fusion-guided TB [TB-FUS]). SB and TB positivity for cancer and sampling quality (mean longest core cancer length, Gleason score) were compared. Clinically significant PCa was any 3 mm or greater core cancer length or any greater than 3 Gleason pattern for SB or any cancer length for TB. Statistical analysis included t test, paired χ(2) test, and κ statistic. Primary end point (core cancer length) was calculated (paired t test).

RESULTS: Among 95 patients (median age, 65 years; mean prostate-specific antigen level, 10.05 ng/mL [10.05 μg/L]), positivity rate for PCa was 59% (n = 56) for SB and 69% (n = 66) for TB (P = .033); rate for clinically significant PCa was 52% (n = 49) for SB and 67% (n = 64) for TB (P = .0011). Cancer was diagnosed through TB in 16 patients (17%) with negative SB results. Mean longest core cancer lengths were 4.6 mm for SB and 7.3 mm for TB (P < .0001). In 12 of 51 (24%) MR imaging targets with positive SB and TB results, TB led to Gleason score upgrading. In 79 MR imaging targets, positivity for cancer was 47% (n = 37) with TB-COG and 53% (n = 42) with TB-FUS (P = .16). Neither technique was superior for Gleason score assessment.

CONCLUSION: Prebiopsy MR imaging combined with transrectal US-guided TB increases biopsy performance in detecting PCa, especially clinically significant PCa. No significant difference was observed between TB-FUS and TB-COG for TB guidance.