Racial variation in positive prostate needle biopsy templates, which include the transition zone.

Abstract

125 Background: Reports have suggested that African Americans (AA) with prostate cancer (PCa) have both increased incidence and increased aggressiveness of tumors located in the transition zone (TZ). Our goal was to evaluate the utility of TZ−directed prostate biopsies in a predominantly AA population at a Veterans Affairs Hospital. Methods: After obtaining IRB approval, we retrospectively reviewed all patients with PCa found on a 14 core biopsy in which 12 needle biopsies were directed at the peripheral zone (PZ) and 2 at the TZ, between January 2010 and June 2014. Location of disease was determined by the results of the biopsy, either PZ alone, TZ alone or both. Aggressiveness of disease was defined by Gleason grade, percent involvement of PCa in any core and NCCN risk-stratification. Self−identified race was recorded for all patients. A series of Mann Whitney U and Chi−square tests were used to compare variables. Results: The total patient cohort consisted of 398 men, in which 277 (70%) were AA. When compared with Caucasian Americans (CA), AA patients had more NCCN intermediate or high risk (50% vs 39%, p = 0.25) PCa. Most patients had PCa limited to the PZ only (n=190) or in both the PZ and TZ (n=191). For 17 patients (4%) PCa was limited to TZ core(s) only, 14 (5%) AA vs 3 (2%) CA (p = 0.24). Of these 17 patients, 14 (82%) had Gleason 6 only disease. Patients with PCa in both the PZ and TZ had higher PSA and PSA density, greater volume of disease, higher-grade lesions and worse NCCN category (all values p <0.01) compared with patients in which the positive biopsy was limited to the PZ. Of these 191 TZ and PZ positive patients, a greater proportion were AA (n=135, 49%) compared to CA (n=56, 46%) (p = 0.48). For patients with PZ and TZ disease, the TZ had the highest-grade in 21 (11%) men, 10% AA and 13% CA (p = 0.67). For most patients (89%), PZ tumor grade was equal to or greater than TZ. Conclusions: TZ−directed prostate needle biopsy cores were rarely the sole location of PCa and when found were usually low grade without clear racial variation. Patients with PCa in both the PZ and TZ had aggressive disease regardless of race although the TZ core resulted in upgrading in a minority of patients. TZ-directed biopsies do not appear to be of greater benefit to AA than CA.