Physician- and Practice-Level Variation in Clinical Trial Participation Among Patients With Advanced Cancer
9 affiliations
- 1Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
- 2Peter O’Donnell Jr School of Public Health, University of Texas Southwestern Medical Center, Dallas
- 3Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas
- 4Ascension, St. Louis, Missouri
- 5Department of Medicine, Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City
- 6Surveillance, Prevention, and Health Services Research, American Cancer Society, Atlanta, Georgia
- 7Department of Hematology and Oncology, Kaiser Permanente Southern California Permanente Medical Group, Riverside, California
- 8Department of Radiation Oncology, Emory University School of Medicine, Atlanta, Georgia
- 9Winship Cancer Institute, Emory University, Atlanta, Georgia
Abstract
Importance: Clinical trial enrollment is essential to advancing cancer care, yet participation among patients with advanced cancer remains low. While patient-level barriers are frequently cited, the role of health care delivery factors—specifically physician- and practice-level variation—has been poorly quantified.
Objective: To quantify variation in clinical trial participation and identify associated delivery system factors among patients with advanced cancer.
Design, Setting, and Participants: This cohort study included adults with advanced or metastatic cancers diagnosed and treated between January 1, 2011, and December 31, 2024, by 1664 physicians across 107 trial-available oncology practices across the US. Data were obtained from the Flatiron Health Research Database. Analyses were conducted between January and April 2025.
Exposures: Patient-level (eg, demographic characteristics, cancer type, and performance status), physician-level (eg, patient volume, subspecialization, and prior trial enrollment activity), and practice-level (eg, size, research engagement, and patient composition) factors.
Main Outcomes and Measures: The primary outcome was clinical trial participation, defined as receipt of a clinical study drug. Mixed-effects logistic regression models were used to decompose the proportion of variation attributable to patient-, physician-, and practice-level factors. Multivariable logistic regression was used to identify characteristics associated with trial participation.
Results: Among the 205 743 patients with advanced or metastatic cancer (mean [SD] age at advanced cancer diagnosis, 67.5 [11.3]; 107 370 males [52.2%]), 10 785 (5.2%) participated in a clinical trial over the study period, increasing from 235 of 5964 (3.9%) in 2011 to 638 of 9336 (6.8%) in 2024. Participation remained highly concentrated: of 1664 physicians, 389 (23.4%) accounted for 9018 (83.6%) of all enrollments (10 785), while 21 of 107 practices (19.6%) accounted for 8686 (80.5%) of all enrolled patients. Additionally, 494 of 1664 physicians (29.7%) enrolled no patients. Physician-level (12.3%) and practice-level (15.1%) factors explained a greater share of variation in trial participation than observable patient-level characteristics (11.4%), with physician- and practice-level contributions increasing over time. Physician’s subspecialization (treated 1-2 cancer groups: odds ratio [OR], 4.11 [95% CI, 2.53-6.68], P = .002; treated 3-4 cancer groups: OR, 2.38 [95% CI, 1.37-4.14], P < .001), physician’s prior trial enrollment activity (enrolled patients in the 2 previous years: OR, 1.58; 95% CI, 1.43-1.76; P < .001), and practice’s research engagement (OR, 2.68; 95% CI, 2.12-3.39; P < .001) were associated with higher odds of trial participation.
Conclusions and Relevance: In this cohort study of patients with advanced cancer, clinical trial participation increased moderately but remained low over the study period, with physician- and practice-level factors consistently accounting for a substantial share of participation variation. Improving trial accrual requires interventions targeting structural factors in enrollment, including research infrastructure and physician engagement.
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BibTeX
@article{jiang2026physician,
title = {{Physician- and Practice-Level Variation in Clinical Trial Participation Among Patients With Advanced Cancer}},
author = {Changchuan Jiang and Chuan Angel Lu and Joshua M. Liao and Ryan D. Nipp and K. Robin Yabroff and Helen H. Moon and Song Zhang and Xin Hu and Tian Zhang},
journal = {JAMA Network Open},
year = {2026},
month = oct,
doi = {10.1001/jamanetworkopen.2026.33046},
url = {https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2854879},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Physician- and Practice-Level Variation in Clinical Trial Participation Among Patients With Advanced Cancer
AU - Changchuan Jiang
AU - Chuan Angel Lu
AU - Joshua M. Liao
AU - Ryan D. Nipp
AU - K. Robin Yabroff
AU - Helen H. Moon
AU - Song Zhang
AU - Xin Hu
AU - Tian Zhang
PY - 2026
DA - 2026/10/06
JO - JAMA Network Open
DO - 10.1001/jamanetworkopen.2026.33046
UR - https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2854879
AB - Importance: Clinical trial enrollment is essential to advancing cancer care, yet participation among patients with advanced cancer remains low. While patient-level barriers are frequently cited, the role of health care delivery factors—specifically physician- and practice-level variation—has been poorly quantified. Objective: To quantify variation in clinical trial participation and identify associated delivery system factors among patients with advanced cancer. Design, Setting, and Participants: This cohort study included adults with advanced or metastatic cancers diagnosed and treated between January 1, 2011, and December 31, 2024, by 1664 physicians across 107 trial-available oncology practices across the US. Data were obtained from the Flatiron Health Research Database. Analyses were conducted between January and April 2025. Exposures: Patient-level (eg, demographic characteristics, cancer type, and performance status), physician-level (eg, patient volume, subspecialization, and prior trial enrollment activity), and practice-level (eg, size, research engagement, and patient composition) factors. Main Outcomes and Measures: The primary outcome was clinical trial participation, defined as receipt of a clinical study drug. Mixed-effects logistic regression models were used to decompose the proportion of variation attributable to patient-, physician-, and practice-level factors. Multivariable logistic regression was used to identify characteristics associated with trial participation. Results: Among the 205 743 patients with advanced or metastatic cancer (mean [SD] age at advanced cancer diagnosis, 67.5 [11.3]; 107 370 males [52.2%]), 10 785 (5.2%) participated in a clinical trial over the study period, increasing from 235 of 5964 (3.9%) in 2011 to 638 of 9336 (6.8%) in 2024. Participation remained highly concentrated: of 1664 physicians, 389 (23.4%) accounted for 9018 (83.6%) of all enrollments (10 785), while 21 of 107 practices (19.6%) accounted for 8686 (80.5%) of all enrolled patients. Additionally, 494 of 1664 physicians (29.7%) enrolled no patients. Physician-level (12.3%) and practice-level (15.1%) factors explained a greater share of variation in trial participation than observable patient-level characteristics (11.4%), with physician- and practice-level contributions increasing over time. Physician’s subspecialization (treated 1-2 cancer groups: odds ratio [OR], 4.11 [95% CI, 2.53-6.68], P = .002; treated 3-4 cancer groups: OR, 2.38 [95% CI, 1.37-4.14], P < .001), physician’s prior trial enrollment activity (enrolled patients in the 2 previous years: OR, 1.58; 95% CI, 1.43-1.76; P < .001), and practice’s research engagement (OR, 2.68; 95% CI, 2.12-3.39; P < .001) were associated with higher odds of trial participation. Conclusions and Relevance: In this cohort study of patients with advanced cancer, clinical trial participation increased moderately but remained low over the study period, with physician- and practice-level factors consistently accounting for a substantial share of participation variation. Improving trial accrual requires interventions targeting structural factors in enrollment, including research infrastructure and physician engagement.
SN - 2574-3805
ER -