Purpose: We performed a multiregistry analysis to assess relative differences in accrual sufficiency and race/ethnicity reporting in trials of common urological cancers and other nonurological solid organ tumors.
Materials and methods: We queried ClinicalTrials.gov and the ISRCTN (International Standard Randomised Controlled Trial Number) Registry for closed phase III and IV trials focused on prostate, colorectal, kidney, bladder, testicular, breast and lung cancer. Identified trials were cross-verified with appropriate published data sources. Comparative accrual sufficiency and rates of race/ethnicity reporting were calculated. Multivariable logistic regression analysis was performed to determine factors associated with accrual status and race/ethnicity reporting.
Results: A total of 326 trials were identified based on our prespecified criteria, of which 63% reported sufficient accrual by time of closure and 58% reported data by race/ethnicity. Nonurological trials were significantly more likely to mention race data than urological trials (OR 3.25, 95% CI 1.24-8.55, p = 0.02). Industry sponsored trials were more likely to meet accrual targets than government funded projects (OR 5.44, 95% CI 1.64-18.20, p = 0.001). Although funding source did not influence race reporting, the reported recruitment of participants of African ethnicity was lower in industry sponsored trials (11.49% vs 3.18%, p <0.01). Two-thirds of the studies did not report baseline characteristics by African American race/ethnicity.
Conclusions: Insufficient accrual and inadequate race/ethnicity reporting are prevalent issues, limiting interpretation of the results of clinical trials of major solid organ malignancies. Addressing these shortcomings would enhance result validity by raising statistical power and improving the transparency of reporting to better evaluate the generalizability of results.
Keywords: African Americans; clinical trial protocols as topic; registries; research design; urogenital neoplasms.