Three-dimensional computer-simulated prostate models: Lateral prostate biopsies increase the detection rate of prostate cancer

Objectives. Urologists routinely use the systematic sextant needle biopsy t echnique to detect prostate cancer. However, recent evidence suggests that this technique has a significant sampling error. We developed a novel three -dimensional (3D) computer-assisted prostate biopsy simulator based on whol e-mounted step-sectioned radical prostatectomy specimens to compare the dia gnostic accuracy of various prostate needle biopsy protocols. Methods. We obtained digital images of 201 step-sectioned whole-mounted rad ical prostatectomy specimens. 3D computer simulation software was developed to accurately depict the anatomy of the prostate and all individual tumor foci. Additional peripheral devices were incorporated into the system to pe rform interactive prostate biopsies. We obtained 18 biopsies of each prosta te model to determine the detection rates of various biopsy protocols. Results. The 10- and 12-pattern biopsy protocols had a 99.0% detection rate ; the traditional sextant biopsy protocol rate was only 72.6%. The 5-region biopsy protocol had a 90.5% detection rate and the 14-pattern, which inclu des all the biopsies used in the patterns above, only added 1 additional po sitive case (99.5%). Transitional zone and seminal vesicle biopsies did not result in a significantly increased detection rate when added to the patte rns above. Only one positive model was obtained when the transitional zone biopsies were added, The lateral sextant pattern had a detection rate of 95 .5%, and the 4-pattern lateral biopsy protocol had a 93.5% detection rate. Conclusions. Our results suggest that all the biopsy protocols that use lat erally placed biopsies based on the 5-region anatomic model are superior to the routinely used sextant prostate biopsy pattern. Lateral biopsies in th e mid and apical zones of the gland are the most important. UROLOGY 53: 961 -967, 1999. Published by Elsevier Science Inc.