Repeat biopsy strategy in patients with atypical small acinar proliferation or high grade prostatic intraepithelial neoplasia on initial prostate needle biopsy

Purpose: Isolated high grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation on prostate biopsy increases the risk of identifying cancer on repeat biopsy. We report the results of repeat prostate biopsy for high grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation, and propose an optimal repeat biopsy strategy. Materials and Methods: Of 1,391 men who underwent standard systematic sextant biopsy of the prostate 137 (9.8%) had isolated high grade prostatic intraepithelial neoplasia or atypical small acinar proliferation, including 100 who underwent repeat prostate biopsy within 12 months of the initial biopsy. Results: Adenocarcinoma was detected in 47 of the 100 patients who underwent repeat biopsy. The initial biopsy site of high grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation matched the sextant location of cancer on repeat biopsy in 22 cases (47%). Repeat biopsy directed only to the high grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation site on initial biopsy would have missed 53% of cancer cases. In 12 of the 47 men (26%) cancer was limited to the side of the prostate contralateral to the side of high grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation. Of the 31 patients with cancer in whom the transition zone was sampled cancer was limited to the transition zone in 4 (13%) and evident at other biopsy sites in 13 (42%). The only significant predictor of positive repeat biopsy was mean prostate specific antigen velocity plus or minus standard error (1.37 ± 1.4 versus 0.52 ± 0.8 ng./ml. per year, p <0.001). Conclusions: Patients with isolated high grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation on prostate biopsy are at 47% risk for cancer on repeat biopsy. The optimal repeat biopsy strategy in this setting should include bilateral biopsies of the standard sextant locations. We also strongly recommend that transition zone sampling should be considered.