Incidence, grade and distribution of prostate cancer following transperineal template-guided mapping biopsy in patients with atypical small acinar proliferation.

PURPOSE: To evaluate the role of transperineal template-guided mapping biopsy (TTMB) in patients with atypical small acinar proliferation (ASAP) diagnosed via transrectal ultrasound-guided needle biopsy (TRUS).

METHODS: In total, 132 consecutive patients with TRUS-diagnosed ASAP underwent TTMB by means of an anatomic-based technique with sampling of 24 biopsy regions. For each of the 24 regions, 1-3 biopsy cores were obtained (depending on prostate size). No patient underwent pre-biopsy MRI imaging. The Gleason score, location of each positive biopsy core, the number of biopsy cores and percent involvement of each core were recorded. Anterior versus posterior cancer distribution was determined for both low- and high-grade (Gleason score ≥7) cancer.

RESULTS: The mean patient age was 63.8 years with a mean PSA of 6.8 ng/mL. Of the 132 patients, 86 (65.2%) were diagnosed with prostate cancer. Of the entire cohort, 47 patients (54.7% of cancer patients and 35.6% of the entire cohort) were diagnosed with Gleason score ≥7. For both low- and high-grade cancers, the anterior gland and especially the anterior apex were the most common cancer locations.

CONCLUSION: In patients with ASAP, TTMB diagnosed prostate cancer in 65.2% of patients and 35.6% of the entire cohort had high-grade prostate cancer. A predilection for anterior-based cancers, especially the anterior apex, was identified. Our study may serve as a baseline reference for MRI-guided biopsy regimens.