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 aty pical small acinar proliferation on prostate biopsy increases the risk of i dentifying cancer on repeat biopsy. We report the results of repeat prostat e 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 sexta nt biopsy of the prostate 137 (9.8%) had isolated high grade prostatic intr aepithelial neoplasia or atypical small acinar proliferation, including 100 who underwent repeat prostate biopsy within 12 months of the initial biops y. Results: Adenocarcinoma was detected in 47 of the 100 patients who underwen t repeat biopsy. The initial biopsy site of high grade prostatic intraepith elial neoplasia and/or atypical small acinar proliferation matched the sext ant location of cancer on repeat biopsy in 22 cases (47%). Repeat biopsy di rected only to the high grade prostatic intraepithelial neoplasia and/or at ypical 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 si de of the prostate contralateral to the side of high grade prostatic intrae pithelial neoplasia and/or atypical small acinar proliferation. Of the 31 p atients with cancer in whom the transition zone was sampled cancer was limi ted 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 ne oplasia and/or atypical small acinar proliferation on prostate biopsy are a t 47% risk for cancer on repeat biopsy. The optimal repeat biopsy strategy in this setting should include bilateral biopsies of the standard sextant l ocations. We also strongly recommend that transition zone sampling should b e considered.