African-American men with low-grade prostate cancer have higher tumor burdens: results from the Duke Prostate Center

BACKGROUND: To investigate racial differences in tumor burden (cancer volume, cancer percentage and cancer to PSA ratios) in a large cohort of men undergoing radical prostatectomy (RP). METHODS: Demographic, clinical and pathological data of patients undergoing RP between 1993-2010 were reviewed and compared between African-American (AA) and non African-American (nAA) men. Further assessments of pathological tumor burden (estimated tumor volume, percent of cancer involvement, and estimated tumor volume/PSA ratios) were performed across Gleason score categories. RESULTS: Of 4157 patients in the analysis, 604 (14.5%) were AA. Overall, AA patients were younger, had higher Gleason scores, PSA levels and incidence of palpable disease (all Po0.001). Despite comparable prostate weights (39.4 vs. 39.6g), AA men had higher percent cancer involvement and estimated tumor volume (all P0.05). When stratified by Gleason scores, prostate weights were comparable;however, estimated tumor volume, percent cancer involvement and estimated tumor volume/PSA ratios were higher in AA men with low grade (≤ 6) prostate cancer (PCa), similar in intermediate grade (7-8) and lower in high grade (9-10) PCa compared to nAA men. CONCLUSIONS: In this large series, AA patients had higher disease burden (estimated tumor volume, percent cancer involvement, estimated tumor volume/PSA ratios) compared to nAA but this association was especially pronounced in low grade (Gleason p6) cancers. These data depict a complex picture of relations between race and tumor burden across the spectrum of Pca aggressiveness. Further investigation is warranted to understand the mechanisms of racial disparities in PCa. Prostate Cancer and Prostatic Disease (2013) 16, 90-93; doi: 10.1038/pcan.2012.39; published online 2 October 2012 Keywords: race; tumor volume; grade nAA P value nAA P value