MRI/US fusion-guided biopsy to detect clinically significant prostate cancer in the central gland correlating with index lesion

44 Background: Central gland (CG) prostate cancers (CaP) are reported with lesser incidence and smaller tumor volume compared to the peripheral zone (PZ). Index tumor lesions defined by highest grade may be missed when in the CG. MRI/US fusion-guided biopsy allows targeting of lesions, potentially identifying cancer outside the traditional TRUS biopsy template. Methods: Retrospective review of 1,003 patients who underwent multiparametric MRI (mpMRI) found 2,119 suspicious lesions. Targets were biopsied and stratified by zonal distribution, CG or PZ. Cancer detection rates (CDR) were tabulated by location and correlated with PSA, Gleason score, prostate volume and MRI suspicion. Results: Fusion-guided biopsy targeted lesions in the central (711, 34%) or peripheral (1408, 66%) prostatic zones. CDR was similar between zones: 35.2% CG compared to 33.6% PZ (Table). CDR of clinically significant disease (Gleason >4+3) was similar in the CG and PZ despite higher prostate volume in those with CG lesions. In contrast to TRUS biopsy, upgrading occurred in 18.5% of CG patients versus 13.3% PZ (p=0.024). 36.6% (77/210) of CG lesions represented the highest risk lesion on MRI, translating to 13% (77/592) of the biopsy-proven CaP cohort. Conclusions: CG cancers occur at a similar frequency as PZ CaP. CG lesions were more likely to be upgraded from TRUS biopsy, frequently representing the index lesion. In upgraded patients, CG targets constituted the index lesion in a third of all males. MRI/US fusion-guided biopsy identifies clinically significant disease of the CG not captured on traditional biopsy. [Table: see text]