Background. Significant racial disparities exist in PCa, with the incidence in African- Americans (AAs) being 50% higher than European Americans (EAs) and PCa mortality rates in AAs being more than two-fold higher. However, the disparity cannot be explained by screening, access to treatment, and genetics can only partially explain the disparity that does little to confer actionable clinical relevance. Currently, only 3 definitive risk factors for PCa have been identified: age, race, and family history of PCa. Smoking has not been an established risk factor for prostate cancer (PCa), and has not been emphasized in PCa prevention. However, recent studies have shown increasing evidence that there is a higher risk of biochemical recurrence, PCa mortality, and metastasis among current smokers, presenting an urgent need in re- evaluating the association between smoking and aggressive PCa. This study aimed to determine whether smoking increase the likelihood of developing a more aggressive prostate cancer. Methods. The study used data from the North Carolina–Louisiana Prostate Cancer Project (PCaP), which is a population-based study of incident PCa conducted between years 2004-2009 in 2 southern states where significant racial disparities in PCa are observed. Because PCa is over diagnosed and most PCa is not clinically relevant, this study will include only subjects with high (Gleason score ≥ 8; PSA > 20 ng/mL; Gleason score = 7 and stage T3–T4) or low (Gleason score < 7 and stage T1–T2 and PSA <10 ng/mL) PCa aggressiveness. 1,497 participants were included in the analysis. Chi square and t-tests were used for the variables of interest and possible confounders, and multivariable logistic regression models were used for the odds ratio estimate. Results. There were 44.9% AAs and 55.1% EAs in the study. AA participants were significantly younger (mean=61.8, SD=7.9) compared with EAs (mean=64.0, SD=7.9), with lower education levels, shorter smoking cessation period, less screening tests in the past, less cigarettes per day, and higher Gleason sum.

From the analysis, more AAs (57.6%) and those who were current smokers (22.7%) were diagnosed with high aggressive PCa. Current smokers had a 2.4 times- higher risk of high aggressive PCa (unadjusted OR=2.42, adjusted OR=2.39); when stratified by race, the risk diminished for EAs (OR=1.30) but increased for AAs (OR=3.36).

Conclusion. Our study shows increased risk of aggressive PCa for current smokers, especially among AAs. Previous study had shown that self-reported cigarettes per day predicts smoke intake more poorly in AAs than in EAs. Thus, there is an urgent need in validated research using biomarkers to confirm the relationship of smoking and aggressive PCa, since cigarette smoking is preventable but have not been emphasized in PCa prevention.

Citation Format: Ping-Ching Hsu, Shelbie Stahr, Christopher Brazeal, Elizabeth H. Fontham, L. Joseph Su. Smoking as a risk factor for the aggressive prostate cancer for African-American men from the North Carolina–Louisiana Prostate Cancer Project (PCaP) [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-201.