Introduction: Publication bias has been raised as concern in reporting clinical trials with negative results. However, little is known about the degree of publication bias from clinical trials with negative results for prostate cancer. Thus, we sought to elucidate the association of enrollment into a clinical trial and all-cause mortality from a population-based cohort of men with advanced prostate cancer in the U.S. Methods: From CancerLinQ, a large national database of community oncology practices, all men with N1 and/or M1 advanced prostate cancer were identified from 2011 to 2021. The primary outcome was all-cause mortality. Multivariable Cox Proportional Hazards were used to test the association of overall survival and clinical covariates including clinical trial enrollment. Results: During the study interval, we identified 139,971 men diagnosed with advanced prostate cancer. With a median follow-up of 58 months, only 2.3% of patients were enrolled into a clinical trial (n = 3,269). On multivariable analysis adjusting for disease features, Asian (HR: 0.61; p < 0.001) race and Hispanic/Latino origin (HR: 0.68; p < 0.001) were associated with lower risk of all-cause mortality. Higher ECOG performance status also correlated with higher risk of all-cause mortality (all p < 0.001). However, patients enrolled into clinical trials had higher risk of all-cause mortality compared to those patients who were not enrolled (HR: 1.18; p < 0.001). Conclusions: In this population-based cohort of advanced prostate cancer patients, clinical trial enrollment was associated with a higher risk of all-cause mortality. We controlled for pertinent prognostic variables, but it remains possible that poorer prognosis patients are triaged to clinical trials. However, an alternate explanation is that some trials do have worse outcomes than standard of care and these findings raise concern that negative clinical trial results are rarely disseminated. SOURCE OF Funding: Schramm Foundation
