Participation in Surgical Oncology Clinical Trials: Gender-, Race/ethnicity-, and Age-based Disparities

Objective: To characterize the representation of racial/ethnic minorities, women, and older persons among participants in surgical trials sponsored by the National Cancer Institute (NCI).

Methods: The NCI Clinical Trial Cooperative Group surgical oncology trials database was queried for breast, colorectal, lung, and prostate cancers treated during the period 2000-2002 (n=13,991). Data from the SEER program and the Census were used to estimate age-, gender-, and race/ethnicity-specific incidence of the same cancers among U.S. adults during the same period. Enrollment fraction (EF), defined as the number of trial enrollees divided by the estimated U.S. cancer cases in each demographic group, was the primary outcome measure. Logistic regression was used to compare the enrollment of racial/ethnic, gender and age subgroups in this analysis.

Results: Relative to white patients (EF=0.72%), lower EFs were noted in African-American (0.48%, odds ratio [OR] vs whites 0.67, P<0.001), Hispanic (0.54%, OR 0.76, P<0.001), and Asian/Pacific islander (0.59%, OR 0.82, P=0.001) patients. Overall, women were more likely to enroll in surgical trials (1.12%) than men (0.22%, OR 5.06, P<0.001). Patients 65-74 years of age (EF 0.45%) were less likely to be enrolled than those 20-44 years of age (EF=2.28%, OR 0.20, P=0.001).

Conclusions: The enrollment in surgical oncology trials is very low across all demographics. However, racial/ethnic minorities and older persons are less likely to be enrolled in cooperative group surgical oncology trials than are whites and younger patients. The high EF for women is due to the high availability of trials for women with breast cancer. Strategies to increase accrual to surgical trials and ameliorate disparities related to race/ethnicity, gender, and age are needed.