Decreasing Clinical Trial Participation Barriers

Today we are discussing cancer clinical trial participation with Joseph Unger, PhD, MS, a health services researcher and biostatistician who is part of the public health sciences division at the Fred Hutchinson Cancer Research Center in Seattle and an assistant professor at the University of Washington’s School of Public Health. Professor Unger focuses on ways to decrease the barriers for cancer patients to enroll in clinical trials and analyzes big data to understand clinical trial participation statistics and trends.

Cancer Network: First, can you talk about cancer clinical trial participation in general? Are there certain characteristics that make certain patients more likely to take part in a clinical trial?

Dr. Unger: Thank you for your interest in the research of our team and for having me participating in this podcast. Clinical trials are the key step in the process of showing that new treatments work and they can only be conducted if patients are willing to participate in them. So, from this perspective, patient participation in clinical trials forms the backbone of cancer clinical research. But, few adult cancer patients actually participate in clinical trials and the percentage is usually estimated to be around 5 percent. Moreover, the patients that do participate tend to be younger than the average cancer patient, they tend to be healthier than the average cancer patient, and they tend to have higher income than the average cancer patient.

Cancer Network: You and your colleagues recently conducted a study, asking the question of how we can increase cancer clinical trial participation. Could you describe the study’s design?

Dr. Unger: One reason that clinical trial participants are usually younger and healthier than the average cancer patient is due to the way that clinical trials are designed.

Clinical trials typically exclude patients with other disease conditions otherwise known as co-morbidities, out of concern for patients’ safety. Also, researchers try to establish trials comprised of patients with similar health profiles so that they can more accurately assess the response of patients to different treatments. One concern that has grown over time is that trials have become too restrictive, excluding patients with co-morbidities who would be reasonable candidates for participation otherwise.

For instance, patients with a prior cancer are often excluded even though the population of cancer survivors in the US is 15 million and growing and many of these patients would be good candidates for participating in a clinical trial for a new cancer. Despite the assumed influence of co-morbidities on trial participation, almost no research using patient level data has been conducted around this issue.

We used data from a large national survey of 5,500 cancer patients who were deciding what treatment to undergo for their cancer, including whether they should participate in a clinical trial. This survey was embedded within an online cancer treatment decision tool that was accessible on many cancer websites such as the American Cancer Society. We included patients with breast, lung, and colorectal cancer and we asked patients to report at baseline about their co-morbid conditions or disease conditions on 18 separate conditions that had been previously identified as being important for describing patient prognosis.

We then followed patients to ask them whether they had a discussion with their physician about clinical trial participation, whether or not they were offered a trial, and whether or not they ultimately ended up participating in a trial.

Cancer Network: What did your study find and was there anything that was particularly surprising?

Dr. Unger: We found that patients with one or more co-morbidities were less likely to discuss a clinical trial with their physician. They were also less likely to be offered a clinical trial by their physician and ultimately, they were less likely to participate in a clinical trial. What was somewhat surprising to us was that these patterns held for a broad range of co-morbidities or disease conditions, including several that are often not used in clinical trial designs to exclude patients from trial participation such as hearing loss.

Cancer Network: What has been the reaction to this study? Are there cancer organizations that are working to boost trial participation?

Dr. Unger: The reaction to the study has been quite positive. In particular, stakeholders from the American Society of Clinical Oncology [ASCO], from the Friends of Cancer Research and from the US Food and Drug Administration [FDA] recently recommended the modernization of certain criteria that are routinely used to exclude patients from trials.

We used those criteria to further evaluate the potential impact of modifications of eligibility criteria on clinical trial participation. We found that updating clinical trial eligibility criteria as these groups recommended could provide opportunities for up to 6,000 more patients per year to participate in clinical trials. These changes are currently being implemented across a broad spectrum of cancer studies in the US. They are important to both patients and researchers since they benefit patients by providing more opportunities to receive their care in trials. The participation of more patients will speed the conduct of clinical trials and thus the rate at which beneficial treatments are identified which ultimately benefits all cancer patients.

Cancer Network: Are there other things that those that design clinical trials can do to increase trial participation or if it’s not clear what those factors are, are you looking into other ways to improve clinical trial participation for cancer patients?

Dr. Unger: One aspect of trial participation that has not received enough attention in my mind is that there is an income disparity. Patients with limited financial needs too often end up choosing not to participate out of concerns about how to pay for their participation because of the indirect costs of participation such as travel, time away from work, or child care.  

I believe there needs to be a better system in place in the US to compensate patients with more limited financial means so that financial concerns are not an impediment to their trial participation.

Also, many patients do not participate in trials because a trial is not available at their institution for their type of cancer. This represents a structural barrier rather than a patient barrier and has gone largely ignored. In fact, more than half of patients do not participate in trials for this reason alone. So, these are some of my current and future research interests.