Independent and joint effects of testosterone replacement therapy and statins use on the risk of prostate cancer among white, black, and hispanic men

The associations of testosterone therapy (TTh) and statins use with prostate cancer remain conflicted. However, the joint effects of TTh and statins use on the incidence of prostate cancer, stage and grade at diagnosis, and prostate cancer-specific mortality (PCSM) have not been studied. We identified White (N ¼ 74,181), Black (N ¼ 9,157), and Hispanic (N ¼ 3,313) men diagnosed with prostate cancer in SEER-Medicare 2007–2016. Prediagnostic prescription of TTh and statins was ascertained for this analysis. Weighted multivariable-adjusted conditional logistic and Cox proportional hazards models evaluated the association of TTh and statins with prostate cancer, including statistical interactions between TTh and statins. We found that TTh (OR ¼ 0.74; 95% CI, 0.68–0.81) and statins (OR ¼ 0.77; 95% CI, 0.0.75–0.88) were inversely associated with incident prostate cancer. Similar inverse associations were observed with high-grade and advanced prostate cancer in relation to TTh and statins use. TTh plus statins was inversely associated with incident prostate cancer (OR ¼ 0.53; 95% CI, 0.48–0.60), high-grade (OR ¼ 0.43; 95% CI, 0.37–0.49), and advanced prostate cancer (OR ¼ 0.44; 95% CI, 0.35–0.55). Similar associations were present in White and Black men, but among Hispanics statins were associated with PCSM. Prediagnostic use of TTh or statins, independent or combined, was inversely associated with incident and aggressive prostate cancer overall and in NHW and NHB men. Findings for statins and aggressive prostate cancer are consistent with previous studies. Future studies need to confirm the independent inverse association of TTh and the joint inverse association of TTh plus statins on risk of prostate cancer in understudied populations. Prevention Relevance: The study investigates a potential interaction between TTh and statin and its effect on incident and aggressive prostate cancer in men of different racial and ethnic backgrounds. These results suggest that among NHW and non-Hispanic Black men TTh plus statins reduced the odds of incident prostate cancer, high-grade and advance stage prostate cancer.