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Abstract

In our practice, transperineal template-guided mapping biopsy (TTMB) has proven to be of great use in the diagnosis and intraprostatic staging of prostate cancer. TTMB results in the accurate and complete three-dimensional sampling of the gland, especially the periurethral and apical regions, which are not readily accessible via transrectal ultrasound (TRUS) approaches (especially in obese patients and/or those with large prostates). In our series, patients with 1, 2, and ≥3 prior negative TRUS biopsies have been diagnosed with prostate cancer after TTMB in 55.5%, 41.7%, and 34.4% of cases, respectively. 1 Taira A.V. Merrick G.S. Galbreath R.W. et al. Performance of transperineal template-guided mapping biopsy in detecting prostate cancer in the initial and repeat biopsy setting. Prostate Cancer Prostatic Dis. 2010; 13: 71-77 Crossref PubMed Scopus (226) Google Scholar This diagnostic yield is substantially greater than the 20% and <10% cancer detection rate after 1 and ≥2 repeat TRUS biopsies. 2 Djavan B. Raver V. Zlotta A. et al. Prospective evaluation of prostate cancer detected on biopsies 1,2, 3 and 4: when should we stop?. J Urol. 2001; 166: 1679-1683 Abstract Full Text Full Text PDF PubMed Google Scholar The distribution of cancers identified on initial and subsequent TTMB provides insight as to why TTMB may have a higher cancer detection rate than other biopsy schemes. For patients undergoing TTMB as the initial biopsy procedure, cancer is equally distributed throughout the gland. However, for patients with 1, 2, and ≥3 prior TRUS biopsies, cancer becomes increasingly localized in the anterior gland. 1 Taira A.V. Merrick G.S. Galbreath R.W. et al. Performance of transperineal template-guided mapping biopsy in detecting prostate cancer in the initial and repeat biopsy setting. Prostate Cancer Prostatic Dis. 2010; 13: 71-77 Crossref PubMed Scopus (226) Google Scholar In addition, in TTMB-diagnosed cancer, no significant decrease in Gleason score or tumor volume has been reported in men after a prior TRUS biopsy, which is in stark contrast with the findings of cancer detected by repeat TRUS biopsy. 2 Djavan B. Raver V. Zlotta A. et al. Prospective evaluation of prostate cancer detected on biopsies 1,2, 3 and 4: when should we stop?. J Urol. 2001; 166: 1679-1683 Abstract Full Text Full Text PDF PubMed Google Scholar In our series, which is approaching 800 patients, no patient has undergone rebiopsy with benign pathology after TTMB. Indications for repeat biopsy include prostate-specific antigen (PSA) progression and/or abnormal digital rectal examination (DRE). Importantly, TTMB accurately predicts cancer location within radical prostatectomy specimens in 95% of cases. 3 Conterato D.J. Braccioforte M.H. Moran B.J. Final pathology in patients undergoing radical prostatectomy: a correlation study between stereotactic transperineal prostate biopsy and radical prostatectomy. Int J Radiat Oncol Biol Phys. 2010; 78: S192 Abstract Full Text Full Text PDF Google Scholar Editorial CommentUrologyVol. 77Issue 5PreviewThe authors report the largest to date series of transperineal template-guided mapping biopsies (TTMB) in the setting of a previous negative biopsy, atypical small acinar proliferation or high grade prostatic intraepithelial neoplasia, and persistently elevated prostate-specific antigen. In this study, the authors emphasize the importance of TTMB for accurate sampling of the prostate and specifically the transition zone (TZ) that is largely inaccessible to conventional transrectal diagnostic methods. Full-Text PDF Editorial CommentUrologyVol. 77Issue 5PreviewTemplate-guided transperineal biopsies under general anesthesia are extremely cumbersome procedures that should only be considered under very exceptional circumstances. The authors argue that it is reasonable to perform this procedure when there is a very strong index of suspicion for the presence of cancer in the face of previously negative biopsies. The finding of 278 cancers in 539 previously biopsied men (53.2%) is evidence that the method works, and most of the detected cancers, 84%, were clinically significant. Full-Text PDF