Value of transition zone biopsy in active surveillance of prostate cancer

Purpose For patients on active surveillance there are limited data on transition zone sampling upon followup biopsy. We verified the value of transition zone biopsy in the active surveillance setting. Materials and Methods Our study included 1,059 sets of prostate biopsies from a total of 534 patients on active surveillance at the Johns Hopkins Hospital. Each set comprised at least 14 cores with 2 or more from the transition zone. Of these men 53 underwent radical prostatectomy. Results Patients with tumors in the peripheral zone as well as the transition zone had a higher maximum Gleason score and an increased maximum percent of cancer per core than men with tumor in the peripheral or transition zone only. In 12 of the 534 patients (2.2%) the tumor on active surveillance biopsy was limited to transition zone core(s). Of the 534 patients 11 (2.1%) had tumor with a high Gleason score (greater than 6) or extensive involvement (greater than 50%) of any core exclusively on transition zone biopsy. However, in 10 of 15 radical prostatectomy cases (66.7%) with prior positive transition zone biopsies the tumors had little or no transition zone component. In addition, transition zone status on biopsy had no significant relationship with Gleason score, extraprostatic extension or seminal vesicle involvement at radical prostatectomy. Conclusions Our data suggest that the additional yield is sufficiently low to argue against routine transition zone sampling in men undergoing followup biopsy on active surveillance. However, further study is needed to make definitive recommendations.