UT Southwestern Study Finds About One in Four Physicians Enrolled Most Cancer Trial Patients

A study led by UT Southwestern Medical Center researchers finds that a patient's chance of joining an advanced-cancer clinical trial depended more on which physician and which oncology practice provided care than on measured patient characteristics such as age, cancer type, and physical function. In a Nov. 10 announcement, the Dallas medical school said the analysis was published in JAMA Network Open. This report draws on that university release and on the journal article, "Physician- and Practice-Level Variation in Clinical Trial Participation Among Patients With Advanced Cancer," by Changchuan Jiang and colleagues, published Oct. 6, 2026 (DOI: 10.1001/jamanetworkopen.2026.33046).

The paper is a cohort study of 205,743 adults treated for advanced or metastatic solid tumors between Jan. 1, 2011, and Dec. 31, 2024, using de-identified electronic health records from the Flatiron Health research database. The data came from 1,664 physicians at 107 oncology practices across the United States, "most of which were in community settings, not National Cancer Institute-Designated Cancer Centers," the university release said. Clinical trial participation was defined as receiving an investigational, or clinical study, drug. Overall, 10,785 patients (5.2%) participated during the study period, a figure the release described as "just over 5%." Participation increased from 3.9% in 2011 to 6.8% in 2024.

Enrollment was tightly concentrated. The study found that 389 of 1,664 physicians (23.4%) accounted for 83.6% of all enrollments (9,018 of 10,785), and 21 of 107 practices (19.6%) accounted for 80.5% (8,686 of 10,785). Those are the paper's figures; the university release rounded them to 23% and 84% of physicians' enrollments, and to 20% and 81% of practices'. "Nearly a third of physicians enrolled no patients," the release said; the paper counted 494 of 1,664 physicians (29.7%). "Oncologists across the country have long sensed that a patient's chance of joining a clinical trial depends on which doctor and which clinic they see, and now we have data from more than 200,000 patients to show it," said lead author Changchuan "Charles" Jiang, M.D., M.P.H., an assistant professor of internal medicine in the Division of Hematology and Oncology and of health economics, systems, and policy in the Peter O'Donnell Jr. School of Public Health at UT Southwestern. "That is good news. Unlike a patient's age or cancer type, a doctor's trial habits and a clinic's research support are things a health system can change."

The UTSW-led team determined that characteristics of who treated a patient and where care was delivered explained more variation in participation than differences among patients. In the paper, physician-level factors accounted for 12.3% of the variation and practice-level factors for 15.1%, compared with 11.4% for observable patient-level characteristics. Patients had higher odds of participating when their physicians specialized in fewer types of cancer, had recently enrolled other patients, or worked at research-active practices. "Patients whose physicians focused on one or two cancer types had about four times the odds of joining a trial," the release said; the paper reported an odds ratio of 4.11 (95% confidence interval, 2.53 to 6.68) for physicians who treated one or two cancer groups.

The same analysis found disparities. "Black patients were 26% less likely to participate than white patients," the release said. The paper reported that Black patients had significantly lower odds than White patients, with an odds ratio of 0.74 (95% confidence interval, 0.62 to 0.88), which is a 26% reduction in odds. At practices serving the largest share of patients from low-income areas, the release said, "the odds of participation were less than half of those at other practices." The paper located that finding in practices in the top 20% for low socioeconomic-status composition, with an odds ratio of 0.42 (95% confidence interval, 0.26 to 0.69). Those figures are from the national records analysis. This report does not extend them to every Texas clinic.

"For many patients with advanced cancer, a trial is a way for patients to access promising new treatment. Our results suggest the chance of being offered one depends on where the patient is treated," said study leader Tian Zhang, M.D., M.H.S., a professor of internal medicine in the Division of Hematology and Oncology at UT Southwestern and associate director of clinical research in the Harold C. Simmons Comprehensive Cancer Center.

The researchers, as described in the announcement, identified potential changes health systems and trial sponsors could make, including pairing physicians new to trial enrollment with experienced mentors, assigning each clinic a dedicated research contact, providing staff support for trial-related testing, using tools to match patients with appropriate trials, building research capacity in clinics that serve low-income communities, and designing simpler trials that smaller sites can run. Jiang said, "We have seen this work in our own safety-net clinics, where patient navigation and physician engagement doubled enrollment of underrepresented patients." The release says he leads an American Cancer Society-funded program to expand prostate cancer trial access at Parkland Memorial Hospital, Dallas County's safety-net hospital, and community sites. That Parkland claim is presented as his account of work in those clinics, not as a result of the national Flatiron analysis.

The authors noted limits that matter for anyone reading the percentages. The database "lacked information on whether individual patients were eligible for specific trials at a given time." Participation "may also have been underestimated because the analysis counted patients only when they received a clinical study drug." The announcement lists additional UTSW contributors, including Joshua Liao, M.D., M.Sc.; Chuan Angel Lu, M.D., M.P.H.; and Song Zhang, Ph.D. It says the study was supported by a Conquer Cancer Career Development Award from the American Society of Clinical Oncology, a Robert Winn Excellence in Clinical Trials Career Development Award, a UT Southwestern Dean's Scholar in Clinical Research award, a Cancer Prevention and Research Institute of Texas grant (RR210079), and a National Cancer Institute Cancer Center Support Grant (P30CA142543).

The findings describe a national records analysis led from Dallas, not a count of how many Texans are now on cancer trials. What the paper and the Nov. 10 release document is the clustering of enrollments among a minority of physicians and practices, the disparity figures the authors reported, and the limits they placed on those numbers. "They that are whole have no need of the physician, but they that are sick" (Mark 2:17).