Feasibility of Cancer Clinical Trial Enrollment Goals Based on Cancer Incidence.



More than 20% of US clinical trials fail to accrue sufficiently. Our purpose was to provide a benchmark for better understanding clinical trial enrollment feasibility and to assess relative levels of competition for patients by cancer diagnosis.


The Database for Aggregate Analysis of ClinicalTrials.gov, up to date as of September 3, 2017, was used to identify actively recruiting, interventional oncology trials with US sites. Observational studies were excluded because not all are registered. Trials were categorized through Medical Subject Headings or free-text condition terms and sorted by cancer diagnosis. Trials that included more than one cancer diagnosis were included in the overall cohort but excluded when evaluating enrollment by cancer type. Trial enrollment slot availability was estimated between September 1, 2017, and August 31, 2018. Availability was estimated from total anticipated enrollment and duration, assuming a constant recruitment rate. Estimates for studies with both foreign and domestic sites were then prorated to calculate available enrollment in the United States alone. Ratios of the number of newly diagnosed patients in the United States available per trial slot were estimated using the American Cancer Society cancer incidence estimates for 2017.


A total of 4,598 interventional oncology trials were identified. Overall, the estimated ratio of newly diagnosed patients available per trial slot was 12.6. Estimated ratios of patients per trial slot for six cancer diagnoses with the highest potential of 12-month US enrollment were as follows: colorectal, 24.7; lung and bronchus, 20.1; prostate, 17.6; breast (female), 13.8; leukemia, 11.6; and brain and other nervous system, 6.0.


For all cancers, successfully accruing trials currently open would require that more than one in every 13 recently diagnosed patients (7.9%) enroll. This ratio and relative difficulty of accrual varies among cancers examined.





Published Version (Please cite this version)


Publication Info

Tran, George, Matthew Harker, Karen Chiswell, Joseph M Unger, Mark E Fleury, Bradford Hirsch, Kimberly Miller, Philip d'Almada, et al. (2020). Feasibility of Cancer Clinical Trial Enrollment Goals Based on Cancer Incidence. JCO clinical cancer informatics, 4(4). pp. 35–49. 10.1200/cci.19.00088 Retrieved from https://hdl.handle.net/10161/28711.

This is constructed from limited available data and may be imprecise. To cite this article, please review & use the official citation provided by the journal.



Karen Chiswell

Statistical Scientist

Ph.D., North Carolina State University - 2007

I work closely with clinical and quantitative colleagues to provide statistical leadership, guidance and mentoring on the design, execution, and analysis of clinical research studies. My work includes design and analysis of observational studies (including large cardiovascular registries, and clinical care databases linked with electronic health record data) and early-phase trials in pediatric populations. My statistical interests include study design, linear and non-linear mixed effects models, survival analysis, biology- and mechanism-based models, and statistical thinking and learning. 


Sheri Tibbs

Team Lead, Web & Mobile

Software developer and contributor to the Code+ program.


Syed Yousuf Zafar

Adjunct Professor in the Department of Medicine

Dr. Zafar is a gastrointestinal medical oncologist and Associate Professor of Medicine, Public Policy, and Population Health Science at the Duke Cancer Institute and Duke-Margolis Center for Health Policy. He serves as Director of Healthcare Innovation at the Duke Cancer Institute. Dr. Zafar also serves as Clinical Associate Director of Duke Forge (Health Data Science Center). Dr. Zafar is considered an international expert in identifying and intervening upon the financial burden of cancer care. His research explores ways to improve cancer care delivery with a primary focus on improving the value of cancer treatment from both patient-focused and policy perspectives.

Dr. Zafar speaks internationally on his research and cancer care delivery. He has over 100 publications in top peer-reviewed journals including the New England Journal of Medicine, the Journal of Clinical Oncology, and JAMA Oncology. His research has been funded by the National Institutes of Health and the American Cancer Society, among others. His work has been covered by national media outlets including New York Times, Forbes, Wall Street Journal, NPR, and Washington Post. He is a Fellow of the American Society of Clinical Oncology.

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