Some Gains Reported in Enrollment Disparity in National Lung Cancer Trials


Key Points

  • The enrollment disparity in national lung cancer trials was significantly reduced among elderly patients and women.
  • Disparities persist among elderly women, blacks, Asian/Pacific Islanders, and Hispanics.

Pang et al found that the enrollment disparity in clinical trials in lung cancer has been reduced in recent years for older patients and women overall, according to a study reported in the Journal of Clinical Oncology. However, disparities persist for elderly women, blacks, Asian/Pacific Islanders, and Hispanics.

Study Details

The study included data from 23,006 National Cancer Institute cooperative group lung cancer trial participants and 578,476 patients with lung cancer from the SEER (Surveillance, Epidemiology, and End Results) registry from 1990 to 2012. Enrollment disparity difference (ie, the absolute difference between the estimated subgroup proportion among U.S. lung cancer population and the subgroup proportion among trial participants) and enrollment disparity ratio (ie, the estimated subgroup proportion among the U.S. lung cancer population divided by the subgroup proportion among trial participants) were calculated.

Changes Over Time

The enrollment disparity for patients aged ≥ 70 years with non–small cell lung cancer improved between 1990 and 2012 (P = .020 for test of parallelism); by 2010 to 2012, the remaining enrollment disparity difference was 0.22, and the enrollment disparity ratio was 1.65.

No improvement in enrollment over time was found for elderly patients with small cell lung cancer, with an annual percentage change of 0.20 (P = .714), compared with an increasing proportion of such patients in the U.S. population (annual percentage change = 0.32, P = .020). By 2012, the enrollment disparity for women with lung cancer had been reduced to an enrollment disparity difference of 0.03 and an enrollment disparity ratio of 1.07; annual percentage changes were 1.65 (P < .001) for trial participants and 0.80 (P < .001) for the U.S. population.

Overall, the enrollment disparity persisted with no significant improvements between 1990 and 2010–2012 for elderly women, blacks (P < .001), Asian/Pacific Islanders (P < .001), and Hispanics (P < .001). Among blacks, the disparity was not significant during the 2010–2012 period; for the 2006–2009 period, the enrollment disparity difference was 0.04, and the enrollment disparity ratio was 1.58.

The investigators concluded: “Under-representation in lung cancer trials improved significantly from 1990 to 2012 for elderly patients with non–small-cell lung cancer and for women, but ongoing efforts to improve the enrollment of elderly patients with [small cell lung cancer] and minorities are needed. Our study highlights the importance of addressing enrollment disparities by demographic and disease subgroups to better target under-represented groups of patients with lung cancer.”

The study was supported by the National Institutes of Health, the National Institute on Aging, and the Health and Medical Research Fund of Hong Kong.

Xiaofei Wang, PhD, of Duke University School of Medicine, is the corresponding author of the Journal of Clinical Oncology article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.