['To investigate if the presence of concomitant high-grade prostatic intraepithelial neoplasia (HGPIN) or atypical small acinar proliferation (ASAP) on biopsy increases the risk of occult adverse pathology in patients otherwise suitable for active surveillance (AS).', "Patients with D'Amico low-risk prostate cancer on ≥ 10-core biopsy who underwent radical prostatectomy at our academic center were evaluated for eligibility for AS by either Epstein criteria or Memorial Sloan Kettering Cancer Center (MSKCC) criteria. Prostatectomy specimens of patients eligible for AS were compared to determine if the presence of clinical HGPIN or ASAP affected the primary outcomes of pathologic upstaging and Gleason score upgrading.", 'Of 553 patients with low-risk prostate cancer, 400 patients (72.3%) met the MSKCC criteria, whereas only 170 patients (30.7%) met the Epstein criteria. HGPIN was present in approximately 32%, and ASAP in approximately 12%, of each AS cohort. On univariate and multivariate analyses, HGPIN and ASAP had no impact on the rate of upgrading and upstaging in either Epstein or MSKCC AS-eligible patients. Furthermore, the presence of HGPIN and ASAP had no impact on the 5-year biochemical recurrence-free survival.'] Does the presence of high-grade prostatic intraepithelial neoplasia or atypia on prostate biopsy adversely affect prostatectomy outcomes for patients otherwise eligible for active surveillance?