Age Disparities in Cancer Trial Patients

Two decades ago, the oncology community was alerted to age disparities in cooperative group studies by an analysis of National Cancer Institute (NCI) funded trials. Older cancer patients have long been underrepresented in clinical trials, despite the disease primarily affecting the aging population. Researchers had not only investigated the disparities in age, but they also noted lesser representation of racial and ethnic minorities, and women.

The latest analysis of oncologic treatment clinical trial cohort demographics reveals a concerning lack of improvement in diversified representation, especially of the aging population.  Today, the median age of trial participants is nearly 7 years younger than the median age of cancer patients and the age gap is worsening, according to new research published online in JAMA Oncology.

Age Disparities Among Cancer Clinical Trial Participants 

Led by Dr. Ethan Ludmir from the University of Texas MD Anderson Cancer Center, a team of researchers aimed to determine the prevalence of age disparities among randomized clinical trial (RCT) participants in oncology, as well as the underlying factors associated with the heightened discrepancies. Dr. Ludmir and colleagues conducted a meta-analysis of 302 phase 3 clinical oncology trials with over 260,000 participants enrolled between 1994 and 2015 using data extracted from ClinicalTrials.gov.

In their analysis, investigators evaluated the difference in median age between trial participant median age and the population-based disease-site-specific median age for each RCT. They found a significant difference in median age of 6.49 years between trial participants and real-world patients with the same cancer site. Moreover, the analysis also revealed that the disparities are growing; the gap between trial patient and real-world patient age decreased by 0.19 years annually, implicating that trial patient demographics are increasingly skewing younger. 

According to the study’s authors, a younger patient cohort is favorable as it can better tolerate toxicities and adverse events than aging populations, which may impact both the results and success of a clinical trial.

Industry-funded vs. Nonindustry-funded Trials

Furthering their investigation, researchers analyzed the age differences in participants of industry-sponsored trials including those involving systemic drugs, radiation, surgery, and supportive care. Of the 302 randomized clinical trials, the overwhelming majority (247 or 82.5%) was industry-funded. Moreover, the investigators found that age disparities were more prevalent among industry-funded trials when compared with non industry-funded studies (-6.84 vs. -4.72 years) – a novel finding that was not examined in previous analyses.

Industry-sponsored trials were not more likely to use enrollment restrictions. However, despite the only 26 trials having age restrictions, study authors report enrollment criteria – such as performance status or age cutoffs – did contribute to discrepancies in age.

Although researchers were not able to conclusively determine the reason behind the widening age gap, they highlight the importance of addressing the issue as the demographic of real-world cancer patients is getting older. According to Dr. Ludmir, 70% of new cancer diagnoses will be given to patients above 65 years by 2030. “The message we’d like to give fellow oncologists: don’t let age alone be the reason a patient is not offered an opportunity to participate in a clinical trial,” he told Medscape Medical News.

Authors hope that their analysis urges reflection and promotes conscientious inclusion of older patients in randomized clinical trials, especially those that are industry-funded to ensure the generalizability of study results and equity in trial access. In recently issued guidelines, the American Society of Clinical Oncology calls for the greater representation of elderly patients in cancer RCTs, which will hopefully encourage future strategies addressing the inequalities.

 
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