Language-based exclusion associations with racial and ethnic disparities in thyroid cancer clinical trials

Background: Racial and ethnic disparities in thyroid cancer care may be mitigated by improving enrollment of more diverse patient populations in clinical trials. We studied trial eligibility criteria and enrollment to assess barriers to equitable representation.

Methods: ClinicalTrials.gov was searched for studies on thyroid cancer treatment conducted between 1993 and 2023. The inclusion and exclusion criteria of each study were examined. For published studies, reported demographic information was collected. Observed enrollment by race was compared with the expected distribution as determined using data from the US Census and the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) databases. Over- and under-representation was defined as the ratio of observed to expected (O/E) enrollment by the race and ethnicity group.

Results: Of 309 thyroid cancer-related trials, 23 (7.4%) used language as an exclusion criterion. Most were interventional (n = 239, 77.3%), university-initiated (194, 62.8%), and drug/device-focused (195, 63.1%). Of studies that excluded by language, 20 (87.0%) were university-initiated. Eighty-eight trials were subsequently published, with 16 (18.2%) reporting race and/or ethnicity distributions. When comparing O/E ratios, White American participants were over-represented (O/E ratio: 1.2, P < .0001). Under-represented groups included Asian/Native Hawaiian (O/E ratio: 0.6, P = .0085), Black (0.6, P = .014), Native American (0.2, P = .072), and Hispanic patients (0.2, P < .0001).

Conclusion: Over the last 3 decades, 1 in 13 thyroid cancer-related clinical trials excluded patients based on language. In the fraction of published studies to report on racial and ethnic demographics, Asian/Native Hawaiian, Black, and Hispanic patients were under-represented. Improved reporting of demographics in published studies and elimination of exclusion criteria such as language that hinder enrollment of minority patients could improve equitable representation of patients in thyroid cancer clinical trials.