Repeat biopsy strategy in men with isolated prostatic intraepithelial neoplasia on prostate needle biopsy

Purpose: Isolated high grade prostatic intraepithelial neoplasia on needle biopsy of the prostate is a strong predictor of malignancy on repeat biopsy. However, the optimal repeat biopsy technique for these patients has not been defined. Materials and Methods: We reviewed the records of 66 men in whom isolated prostatic intraepithelial neoplasia was found on needle biopsy of the prostate. We evaluated the side and/or quadrant and grade of prostatic intraepithelial neoplasia on initial biopsy, and compared the findings to the location of cancer on repeat biopsy. Results: Of 66 men 31 (47%) had cancer on repeat biopsy, with disease on the same side of the prostate as prostatic intraepithelial neoplasia in 20 (64%). The quadrant locations of prostatic intraepithelial neoplasia and cancer matched in 6 of 12 cases (50%). Low and high grade prostatic intraepithelial neoplasia predicted the side of cancer on repeat biopsy in 3 of 5 (60%) and 17 of 26 (65%) cases, respectively. Conclusions: Directing repeat biopsy solely to the side with prostatic intraepithelial neoplasia will miss cancer in approximately 35% of cases. The optimal repeat biopsy technique for patients with high grade prostatic intraepithelial neoplasia should include systematic biopsy of the prostate.