Top Line: Is an MRI-based, targeted biopsy alone approach to initial prostate cancer diagnosis non-inferior to the standard 12-core TRUS biopsy approach?
The Study: In clinical practice, multiparametric MRI and MRI-guided prostate biopsy is often done in addition to rather than in lieu of a standard 12-core TRUS biopsy. While MRI-guided biopsy identifies a higher proportion of clinically relevant prostate cancer, it is unclear if this approach alone is equivalent to standard biopsy or combination biopsy. In this Canadian randomized phase 3 trial, >450 men who were biopsy-naive with clinical suspicion of prostate cancer were randomized to either the standard 12-core TRUS biopsy approach or pre-biopsy MRI and targeted biopsy alone. The purpose was to see if the overall proportion of men diagnosed with grade group 2+ disease was non-inferior with the MRI vs TRUS approach, and the non-inferiority margin for the proportion of GG2+ disease diagnosed was -5%. Men were selected for biopsy based on an estimated 5% or greater risk of grade group 2+ disease using the Prostate Cancer Prevention Trial Risk Calculator. All men in the TRUS arm underwent biopsy, and 30% (n=67) were diagnosed with GG 2+ disease while another 22% were diagnosed with GG 1 disease. In the MRI arm, 62% of men had a PIRADS 3+ lesion for biopsy, and 35% (n=79) were diagnosed with GG 2+ disease while 10% were diagnosed with GG 1 disease. In other words, just as many (if not more) GG 2+ cancers were found with the MRI approach while allowing ⅓ of men to avoid biopsy.
TBL: Compared to standard 12-core TRUS-guided biopsy without MRI, the use of MRI and targeted biopsy alone appears to be non-inferior at diagnosing GG 2+ disease while detecting half as many GG 1 cancers and allowing ⅓ of men to avoid biopsy. | Klotz, JAMA Oncol 2021