Current prostate biopsy protocols cannot reliably identify patients for focal therapy: correlation of low-risk prostate cancer on biopsy with radical prostatectomy findings

Focal therapy appears to be an attractive alternative approach for patients with localized prostate cancer (PCa). Identifying suitable candidates is crucial to the success of focal therapy. Currently, standard transrectal ultrasound (TRUS)-guided prostate biopsy remains the widespread approach to evaluate patient suitability. In this study, we evaluated the ability of current biopsy protocols to predict cancer characteristics in radical prostatectomy (RP) specimens. We reviewed 4437 cases from 2000 to 2008 in our PowerPath database, and identified 158 patients with low-risk cancer, defined as a pre-biopsy PSA level <= 10 ng/mL, unilateral, low tumor volume (<= 5%) and low to intermediate Gleason score (GS <= 6) on first positive prostate biopsy. The pathological characteristics of subsequent RP specimens were reviewed. We found that, of 158 patients with these criteria, 117 (74%) had bilateral cancer, 49 (31%) had increased tumor volume (>= 10%), and 46 (29%) were upgraded to GS >= 7 at RPs. When patients were stratified by total biopsy core numbers, extended biopsy core protocols were not significantly more reliable in identifying unilateral and low volume prostate cancer patients. One core positive on biopsy was not significantly superior to >= 2 positive cores in predicting unilateral, low volume, low stage cancer at prostatectomy. These findings indicate that current standard prostate biopsy protocols have limited accuracy in identifying candidates for focal therapy.