Black Race Predicts Significant Prostate Cancer Independent of Clinical Setting, and Clinical and Socioeconomic Risk Factors: evidence for a biological basis of disparities

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INTRODUCTION

Several studies have linked Black race to prostate cancer (PCa) risk but most fail to account for established clinical factors such as 5-alpha reductase inhibitor (5-ARI) use and prostate volume, socioeconomic status, and hospital setting. We assess whether Black race remains strongly associated with PCa and Gleason ≥3+4 PCa, after adjusting for clinical setting, socioeconomic and clinical factors at prostate biopsy.

METHODS

We recruited 564 men over age 40 undergoing initial prostate biopsy for abnormal PSA or digital rectal examination (DRE) from three publicly funded and two private hospitals from 2009-2014. Information was retrieved from self-administered surveys and electronic health records. Univariate and multivariate analyses examined the associations between hospital type, race, clinical and sociodemographic risk factors with PCa diagnosis and Gleason ≥3+4 PCa. Given changes in PCa screening recommendations, we also performed multivariate analyses for men ages 40 to 54.

RESULTS

Black and White men had similar age, BMI and prostate volume. Black men had higher PSA (8.10 ng/mL vs. 5.63 ng/mL, p <0.001) and PSA density (0.22 ng/mL/cm<sup>3 vs. 0.15 ng/mL/cm3, p <0.001). Black men had higher frequency of cancer (63.1% vs. 41.5%), Gleason ≥3+4 PCa and increased frequency of NCCN High to Metastatic risk stratification (all p <0.05). Blacks had significantly increased rates of Gleason ≥3+4 relative to Whites in both public (27.7% vs 11.6%, p<0.001) and private (48.4% vs 21.6%, p=0.002) settings. In models adjusted for age, first degree family history of PCa, prostate volume, 5-ARI use, hospital type, income, marital and educational status, Black race was independently associated with overall PCa diagnosis (OR =2.13, p =0.002). Additionally, there was a significant multiplicative interaction with Black race x abnormal DRE and Gleason ≥3+4 PCa (OR =2.93, p =0.01). When limiting the analysis to men under 55 years, Black race (13.49, p=0.01) and family history (OR 5.12, p=0.03) were independently positively associated with overall PCa diagnosis for men aged 40 to 54. </p>

CONCLUSION

Black race is independently associated with PCa and Gleason ≥3+4 PCa after accounting for clinical and socioeconomic risk factors including clinical setting and is the strongest PCa risk factor in younger men. Further investigation into optimizing screening in Black men aged 40 to 54 is warranted.

Funding: 1R01MD007105-01 (Kittles) IK2CX000926-01 (Murphy) W81XWH-10-1-0532 pd22E (Murphy) P50CA090386 (Catalona)