Clinical Trial Participants Average 6.5 Years Younger Than Actual Cancer Populations

August 07, 2019 by Elisa Becze BA, ELS, Editor

For the four most common cancer sites (breast, prostate, colorectal, and lung cancer), the median age of patients in clinical trials is an average of 6.5 years younger than the median age of patients diagnosed with that cancer. And the age disparity is worsening, researchers reported in JAMA Oncology (

The researchers looked at data from 262,354 patients who had participated in 302 industry-sponsored and non–industry-sponsored randomized clinical trials from 1994–2015. They found a 4.72-year age difference between trial participants and cancer populations in non–industry-sponsored clinical trials and a 6.84-year age difference in industry-sponsored trials. When they observed the patterns over time, they found that the difference increased 0.19 years annually: despite the increasing age of patients and survivors, clinical trial participants keep getting younger. 

Additionally, they looked at participation in a subset of clinical trials that investigated molecular cancer subtypes or various novel therapies such as targeted agents, both of which are more likely to be industry funded, and found similar age disparities.  

They theorized that industry-sponsored trials were more likely to be conducted at cancer centers that treat a larger population of younger patients and noted that “historically, the federal government has addressed cancer clinical trial enrollment disparities by primarily focusing on sex and race/ethnicity. While prior reports have shown some successes in addressing those imbalances, our data demonstrate that age disparities remain a persistent and worsening problem for oncology clinical trials.” 

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