Introduction:

Adverse social determinants of health (SDOH) may underlie disparities in bladder cancer (BCa) mortality and access to clinical trials. Identifying and overcoming these barriers is essential for the delivery of equitable cancer care. For these reasons, we evaluate the association between clinical trial availability, cancer mortality, and population-level social determinants of health in bladder cancer.

Methods:

Using data linkage from ClinicalTrials.gov, Surveillance Epidemiology and End Results (SEER) Registry, and the Centers for Disease Control and Prevention Social Vulnerability Index (SVI), we performed a cross-sectional analysis of county-level BCa clinical trial availability, BCa incidence and mortality rates, and population-level SDOH. We included Phase 2 and Phase 3 interventional BCa clinical trials (2007 to 2022). Clinical trial availability was defined as the presence of any BCa trial within a county over the study period. BCa mortality and incidence rates were calculated per 100,000 residents ≥50 years of age. BCa trial availability, cancer incidence, and cancer mortality were compared across SVI quintiles (i.e., most socially vulnerable versus least socially vulnerable). Multivariable logistic and linear regression analyses were performed to evaluate the association between SVI and trial availability and BCa mortality, respectively.

Results:

Of the 3,141 counties included in the analysis, 1,151 (36.6%) had any BCa trial, with the most vulnerable counties having a lower proportion compared to the least vulnerable counties (24.0% vs. 41.8%, p<0.05). Further, the most vulnerable counties had a lower BCa incidence rate (mean 61.0 vs. 74.4, p<0.05) and similar BCa mortality rate (mean 16.2 vs. 16.3, p>0.05). On adjusted analysis, increasing SVI was associated with significantly lower odds of having any BCa trial (OR 0.41, 95% CI 0.22 – 0.76) and increased BCa mortality (1.75, 95% CI 0.79 – 2.71), while the presence of any trial was associated with decreased BCa mortality (-1.68, 95% CI -2.20 – -1.15).

Conclusion:

The most vulnerable counties were far less likely to have any BCa clinical trials despite having a similar BCa mortality rate.  The presence of a trial was associated with a reduction in mortality, perhaps representing better developed cancer care infrastructure. These vulnerable counties represent scientifically underserved populations that may benefit from equity-driven expansion of cancer care infrastructure.

Funding: Bladder Cancer Advocacy Network Young Investigator Award