Transperineal Template-guided Mapping Biopsy Identifies Pathologic Differences Between Very-Low-risk and Low-risk Prostate Cancer: Implications for Active Surveillance.

Abstract

Active surveillance (AS) is increasingly utilized for low-grade prostate cancer with the greatest risk being the possibility of missing a high-grade cancer. We evaluate the role of transperineal template-guided mapping biopsy (TTMB) to select patients for AS. A total of 131 consecutive, prospectively evaluated men with transrectal ultrasound-guided needle biopsy (TRUS)-diagnosed very low risk (Gleason score ≤6, ≤2 positive biopsies, prostate-specific antigen [PSA] density <0.15, and ≤50% involvement on any core) and low risk (Gleason score ≤6, clinical stage T1c, and PSA ≤10 ng/mL) underwent TTMB as a staging procedure. Biopsies were obtained corresponding to 24 regional biopsy locations. For each patient, the location of each positive biopsy core, the number of positive cores, and the percentage involvement of each core were reported. After TTMB, TRUS-detected very-low-risk prostate cancer patients were less likely to be diagnosed with higher Gleason score, were less likely to have bilateral involvement, and had statistically fewer number of positive biopsy cores on TTMB. After TTMB, no cancer, very-low-risk, or low-risk prostate cancer was detected in 60 of 72 (83.3%) and 19 of 59 (32.2%) of patients with very low and low risk, respectively. In multivariate analysis, older age and low risk predicted for higher Gleason score at the time of TTMB. Very-low-risk prostate cancer patients have a significantly lower incidence of Gleason score upgrading than those with low-risk disease. After TTMB, 83.3% of patients with very-low-risk and 32.2% of patients with low-risk disease appear to be outstanding candidates for AS.