African-American men with prostate cancer have larger tumor volume than Caucasian men despite no difference in serum prostate specific antigen.

ABSTRACT

INTRODUCTION: Prior studies suggest that among men with low grade prostate cancer, African Americans (AA) produce less prostate-specific antigen (PSA) than Caucasians. We investigated racial differences in PSA, PSA density (PSAD), and tumor volume among men with prostate cancer, regardless of tumor grade. These racial differences, if present, would suggest that AA men may benefit from different screening, surveillance, and treatment regiments compared to Caucasians. MATERIALS AND METHODS: We identified men from our institutional prostate cancer database that underwent radical prostatectomy between 2012 and 2015. Clinicopathologic parameters were compared by race. Multivariable linear regression was then performed to identify factors associated with PSA, PSAD, and tumor volume, adjusting for race, age, body mass index, and pathologic parameters. RESULTS: A total of 255 men were included in the analysis, including 182 (71.4%) Caucasian and 73 (28.6%) AA. PSA (10.2 versus 8.1, p = 0.13) and PSAD (0.23 versus 0.22, p = 0.73) did not differ significantly between AA and Caucasian men. In contrast, tumor volume was significantly greater in AA men (13.4 versus 9.6 grams, p = 0.01). In multivariable linear regression analysis, AA race was not associated with PSA (p = 0.80) or PSAD (p = 0.41), but was significantly associated with increased tumor volume (p < 0.01). CONCLUSIONS: AA men who underwent radical prostatectomy in this analysis had larger tumor volume than Caucasian men despite having similar PSA levels. This association suggests that prostate cancers in AA men may produce less PSA than in Caucasian men. These findings have implications for prostate cancer screening and treatment, as PSA may underestimate the presence or extent of cancer in AA men.