Barriers to Cancer Clinical Trial Enrollment in Early Adolescents and Young Adults

Even when cancer clinical trials are available, fewer eAYAs than children enroll

Significantly fewer early adolescents and young adults (eAYAs; ages 15–21) enroll in cancer clinical trials (CCTs) than children, according to a study in Cancer, although there are equal proportions of CCTs available to both age groups. This could be one reason why there have been significant improvements in the survival of pediatric and older adult patients with cancer that have not been seen in the eAYA population.

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“We’re at a point at which scientific discoveries are happening very quickly,” states Stefanie Thomas, MD, a pediatric oncologist at Cleveland Clinic Children’s. “Looking at CCT participation in this population is important because their cancers are often rare diseases. We need more patients enrolled in CCTs to move science forward at a rate at which the findings would be relevant. In order to accomplish that, we need studies like this that give us insight into enrollment rates, and specifically, factors that might influence enrollment.”

Published in 2018, the study assesses rates of clinical trial enrollment in a group of pediatric and AYA cancer patients seeking care at the Children’s Hospital of Los Angeles (CHLA). Dr. Thomas, first author on the study, is a Cleveland native and Cleveland Clinic Children’s alumnus who completed a post-fellowship in AYA oncology at CHLA and the University of Southern California (USC) before returning to Cleveland Clinic Children’s.

Cancer clinical trial enrollment

In this study, researchers examined clinical trial existence, which they defined as a nationally registered CCT that was appropriate for the patient’s age, diagnosis and stage/risk group, and listed as open and recruiting on Then, according to Dr. Thomas, the team asked if that trial was available locally at CHLA, and whether or not the patient enrolled.

Patients (216) were included if they presented with a new primary cancer diagnosis in a 13-month period. In total, there were 58 eAYA patients and 158 children included. Patient demographics (i.e., age, sex, race/ethnicity) and disease-related data (i.e., cancer diagnosis, stage, grade, risk group and relevant genomics) were extracted from medical records for analysis.

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Analysis revealed similar proportions of CCTs existed and were available for children and eAYAs. However, the 15–21 year olds did not enroll as frequently. Specifically, among those patients with existing and available CCTs, only 30.4% of eAYAs enrolled compared with 67.7% of children.

In terms of predictors of CCT enrollment, patients were less likely to enroll if they were in the eAYA age group. Patients with solid tumors and male patients were also less likely to enroll.

Trial existence and availability are not barriers

Overall, the results confirm a significant enrollment gap, and suggest that CCT existence and availability are not barriers to enrollment as once thought.

“With this project, we sought to look prospectively at each individual patient to see what the trial landscape looked like at that particular time. It was really a deep dive into understanding this enrollment problem,” continues Dr. Thomas. “We were actually pretty surprised by this finding. Lack of trial availability at children’s hospitals is frequently cited as a reason for low CCT enrollment. We expected our results to confirm this supposition. It was surprising that even when a trial is available, these adolescents did not agree to participate in a trial.”

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Next steps

Dr. Thomas is currently assembling baseline CCT enrollment data for Cleveland Clinic Children’s, and hopes to develop interventions that can be implemented to address eAYA trial participation at the institution.

“At Cleveland Clinic, there’s a great relationship between the pediatric and adult oncology services,” says Dr. Thomas. “It’s unique to have these services under the same umbrella, and this collaboration may help increase CCT enrollment among eAYAs with cancer and aid in care transitions.”

More globally, Dr. Thomas believes a paradigm shift is needed to increase eAYA enrollment in clinical trials. In her opinion, efforts should be made to bring studies to patients at their treating hospitals rather than asking them to disrupt their lives to travel for CCTs. Additionally, she believes change is needed in the way that these studies are offered to patients to ensure comprehension.