Evaluating the impact of pre‐diagnostic use of statins and testosterone replacement therapy on mortality outcomes in older men with hormone‐related cancers: Surveillance, Epidemiology, and End Results‐Medicare 2007–2015

The link between the pre-diagnostic use of statins and testosterone replacement therapy and their impact on hormone-related cancers, prostate cancer, colorectal cancer, and male breast cancer survival remains a topic of controversy. Further, there is a knowledge gap concerning the joint effects of statins and testosterone replacement therapy on hormone-related cancer survival outcomes.To examine the independent and joint effects of pre-diagnostic use of statins and testosterone replacement therapy on the risk of all-cause and cause-specific mortality among older men diagnosed with hormone-related cancers, including prostate cancer, colorectal cancer, and male breast cancer.In 41,707 men (≥65 years) of Surveillance, Epidemiology, and End Results-Medicare 2007-2015, we identified 31,097 prostate cancer, 10,315 colorectal cancer, and 295 male breast cancer cases. Pre-diagnostic prescription of statins and testosterone replacement therapy was ascertained and categorized into four groups (Neither users, statins alone, testosterone replacement therapy alone, and Dual users). Multivariable-adjusted Cox proportional hazards and competing-risks (Fine-Gray subdistribution hazard) models were conducted.No significant associations were found in Cox-proportional hazard models for hormone-related cancers. However, in the Fine-Gray competing risk models among high-grade hormone-related cancers, statins alone had an 11% reduced risk of hormone-related cancer-specific death (hazard ratio: 0.89; 95% confidence interval: 0.81-0.99; p 0.0451). In the prostate cancer cohort with both statistical models, the use of testosterone replacement therapy alone had a 24% lower risk of all-cause death (hazard ratio: 0.76; 95% confidence interval: 0.59-0.97; p 0.0325) and a 57% lower risk of prostate cancer-specific death (hazard ratio: 0.43; 95% confidence interval: 0.24-0.75; p 0.0029). Similar inverse associations were found among aggressive prostate cancer cases with testosterone replacement therapy alone and statins alone. No significant associations were found in the colorectal cancer and male breast cancer sub-groups.Pre-diagnostic use of statins and testosterone replacement therapy showed a survival benefit with reduced mortality in high-grade hormone-related cancer patients (only statins) and aggressive prostate cancer patients in both statistical models. Findings of testosterone replacement therapy use in aggressive prostate cancer settings could facilitate clinical trials. Further studies with extended follow-up periods are needed to substantiate these findings.