Clinical‐Pathologic Correlation Between Transperineal Mapping Biopsies of the Prostate and Three‐Dimensional Reconstruction of Prostatectomy Specimens

BACKGROUND: Extended transrectal ultrasound guided biopsies (TRUSB) of the prostate may not accurately convey true morphometric information and Gleason score (GS) of prostate cancer (PCa) and the clinical use of template-guided (5-mm grid) transperineal mapping biopsies (TPMBs) remains controversial. METHODS: We correlated the clinical-pathologic results of 1,403 TPMB cores obtained from 25 men diagnosed with PCa with 64 cancer lesions found in their corresponding radical prostatectomy (RP) specimens. Special computer models of three-dimensional, whole-mounted radical prostatectomy (3D-WMRP) specimens were generated and used as gold standard to determine tumor morphometric data. Between-sample rates of upgrade and downgrade (highest GS and a novel cumulative GS) and upstage and downstage (laterality) were determined. Lesions ≥ 0.5 cm(3) or GS ≥ 7 were considered clinically significant. RESULTS: From 64 separate 3D-WMRP lesions, 25 had significant volume (mean 1.13 cm(3)) and 39 were insignificant (mean 0.09 cm(3)) (P < 0.0001); 18/64 lesions were missed by TPMB, but only one was clinically significant with GS-8 (0.02 cm(3)). When comparing the cumulative GS of TPMB versus RP, 72% (n = 18) had identical scores, 12% (n = 3) were upgraded, and only 16% (n = 4) were downgraded. Laterality of TPMB and RP was strongly correlated, 80% same laterality, 4% were up-staged, and 16% down-staged. CONCLUSIONS: Our clinical-pathology correlation showed very high accuracy of TPMB with a 5-mm grid template to detect clinically significant PCa lesions as compared with 3D-WMRP, providing physicians and patients with a reliable assessment of grade and stage of disease and the opportunity to choose the most appropriate therapeutic options.