Title: Efficient sampling methods in systematic biopsy which could be performed in addition to MRI-guided biopsy
Noboru Numao; Masaya Ito; SoichiroYoshida; Minato Yokoyama; Junichiro Ishioka; YohMatsuoka; KazutakaSaito; Yasuhisa Fujii; Kazunori Kihara
Department of Urology, Tokyo Medical and Dental University, Graduate School, Tokyo, Japan.
Background & Objective
Although usefulness of magnetic resonance imaging (MRI)-guided biopsy (MRBX) has been established, significance of additional systematic biopsy has not been fully elucidated. In this study, we analyzed efficient sampling methods in systematic biopsy which could be performed in addition to MRBX.
Patients and Methods
September 2011 and January 2014 at a single academic center. Prebiopsy 1.5T multiparametric MRI (T2-weighted, diffusion-weighted and/or dynamic contrast-enhanced imaging in principle) and then prostate biopsy.
N = 390
Excluded 108 men because of
PSA >40 ng/ml (n=15), obvious clinical T3-4 disease (n=74), biopsy with fewer cores for severe comorbidity (n=19)
Study cohort : N = 282
MRBX + Systematic 14-core biopsy (S14PBX)
MRBX was performed under cognitive fusion or MRI/TRUS fusion using a real-time virtual sonography system. On MRBX, four-core samplings for one suspicious lesion on MRI were performed.
The S14PBX protocol was a transperineal 14-core biopsy or a combined 14-core biopsy of transperineal 8-core and transrectal 6-core biopsies, and each biopsy included 6 or 4 anterior samplings, respectively.
Significant cancer (SC) was defined as clinical stage ≥ T2b, biopsy Gleason score ≥ 4+3, or maximum cancer length ≥ 5 mm. SC-core was defined as a biopsy cancer core with Gleason score ≥ 4+3 or cancer length ≥ 5 mm.
We assessed SC detected only by S14PBX (missed by MRBX). We assessed SC identified as indolent cancer only by MRBX but upgraded to SC by additional S14PBX. In these SC underestimated by MRBX we assessed positive sampling sites of SC-core in S14PBX, and explored efficient systematic biopsy protocol that can compensate for MRBX-underestimation.
The detection rate of SC using both MRBX and S14PBX was 59% (162/282).
9 SC was detected only by S14PBX (missed by MRBX).
8SC was identified as indolent cancer only by MRBX but upgraded to SC by additional S14PBX.
Transperineal 6-core (bilateral anterior, mid and posterior samplings from the apex) samplings could efficiently identify 12 of the 17 SCs as SC and appears to strike a balance between number of sampling cores in additional systematic biopsy and SC identification.
Balanced combination of MRI-guided biopsy and systematic biopsy
MRBX + Systematic transperineal 6-core biopsy
Additional systematic transperineal 6-core biopsy could efficiently reduce underestimation of MRI-guided biopsy.