Initial diagnosis of insignificant cancer, high-grade prostatic intraepithelial neoplasia, atypical small acinar proliferation, and negative have the same rate of upgrade to a Gleason score of 7 or higher on repeat prostate biopsy.

Extended prostate needle core biopsies are standard of care for the diagnosis of prostatic carcinoma. Subsequent biopsies may be performed for a variety of indications. Knowledge of biopsy characteristics indicating risk for progression may have utility to guide therapeutic management. Prostate needle core biopsies performed between 2008 and 2014 were reviewed. Patients with at least 1 subsequent biopsy were identified. Cases were categorized by worst initial diagnosis. Gleason ≤6 carcinoma was further classified as significant or insignificant with insignificant defined as follows: ≤2 cores with carcinoma, sites with ≤50% carcinoma, and unilateral carcinoma. A total of 329 men underwent repeat biopsies. Gleason ≤6 insignificant carcinoma, high-grade prostatic intraepithelial neoplasia (HGPIN) and/or atypical small acinar proliferation, and negative biopsies had a similar rate of Gleason ≥7 upon repeat biopsy (16%, 17%, 14%; P = .91). Initial biopsy diagnoses of Gleason ≤6 significant carcinoma had a higher rate of Gleason ≥7 on repeat biopsy compared with initial biopsies of Gleason ≤6 insignificant carcinoma (39%, 16%; P = .003). Within initial diagnoses of Gleason ≤6, 1 core compared with more than 1 core positive had a lower rate of Gleason ≥7 on repeat biopsy (17%, 30%), although this difference was not significant (P = .08). An initial biopsy diagnosed as Gleason ≤6 insignificant carcinoma, HGPIN and/or atypical small acinar proliferation, or negative had a similar substantial risk of Gleason ≥7 carcinoma upon subsequent biopsy. Our findings support the continued stratification of Gleason ≤6 and thus the diagnostic workup of all atypical foci to provide an accurate, thorough number of involved cores.