An evaluation of race, ethnicity, age, and sex-based representation in phase I to II renal cell carcinoma clinical trials in the United States.

INTRODUCTION: Enrollment of a representative study population permits generalizable and reliable results for clinical trials. We sought to evaluate whether patients enrolled in trials for advanced renal cell carcinoma (RCC) are representative of the overall population of advanced RCC patients in the United States.
MATERIALS AND METHODS: The clinicaltrials.gov results database was queried for interventional clinical trials directed at clinically advanced (stage III/IV) RCC that enrolled patients from the US only. We identified 375 patients from 18 phase I to II trials that met eligibility criteria. The American College of Surgeons' National Cancer Database (NCDB) which includes data on approximately 70% of all US cancer diagnoses was queried and we identified 75,308 patients with advanced (stage III/IV) RCC. Demographic characteristics were summarized and compared between the 2 populations.
RESULTS: Compared to the US population of advanced RCC (NCDB), significant under-representation in clinical trials was observed for patients aged 65+ (26.3% vs. 50.4%; P<0.001) and among those with Hispanic ethnicity (2.7% vs. 7.2%; P = 0.005). A trend toward under-representation was observed for black patients (7.0% vs. 9.8%, P = 0.076) but not for white patients (89.9% vs. 87.0%, P = 0.107) or other racial groups (P>0.05 for all). Female patients made up 30.3% of trial enrollees and 33.3% of the US advanced RCC population (P = 0.221).
CONCLUSION: Significant under-representation was observed for elderly and Hispanic patients with a trend toward under-representation for black and female patients in phase I to II RCC clinical trials. Greater efforts to include underrepresented populations are necessary to improve the effectiveness and generalizability of clinical trials in kidney cancer.