Black people make up 14 percent of the U.S. population, but only 5-7 percent of clinical trial participants. “In a research analysis of more than 433,000 patients participating in clinical trials in the U.S. between 2010 and 2021, Black people accounted for 15 percent of participants but only 8.5 percent of cancer trial participants,” an ASCO Daily News article reported. One study found that minorities, women, and elderly patients are underrepresented in multiple myeloma clinical trials
These discrepancies in cancer clinical trials underscore the need for better representation in cancer clinical trials, especially since Black patients are disproportionately burdened by several cancer types, including triple-negative breast cancer, prostate cancer, colorectal cancer, lung cancer, and mutiple myeloma.
BlackDoctor spoke with cancer experts about why clinical trials lack diversity and what researchers can do to improve representation in medical research.
Prior studies have shown that cancer treatment effectiveness can vary by race, gender, and age, said Narjust Duma, MD, Associate Director of the Cancer Care Equity Program at Dana-Farber Cancer Institute. Despite this, clinical trials have failed to recruit a diverse patient population to test new drugs and therapies.
“All the data we’re using to guide cancer treatment is for one type of patient,” she said.
Dr. Duma undertook this study after a conversation with a Black lung cancer patient about possible chemotherapy treatments.
“He asked, ‘Where are the numbers about me?'” Dr. Duma recalled. “Where are the numbers about African Americans? What are the chances we respond to treatment?”
A cursory look at chemotherapy research revealed that only a handful of Blacks had been included in clinical trials involving hundreds of people, Dr. Duma said.
To explore the issue further, Dr. Duma and her colleagues analyzed enrollment data from all U.S. cancer therapy trials completed between 2003 and 2016, totaling more than 55,000 participants.
Of those patients, 83 percent were white, 6 percent were Black, just over 5 percent were Asian, almost 3 percent were Hispanic, and around 2 percent were classified as “other,” researchers found.
The Hispanic numbers are particularly troubling, given that they currently make up 16 percent to 20 percent of the U.S. population and that proportion is increasing, Dr. Duma said.
“That’s one-third of the U.S. population, and we have close to zero information about how to treat cancer in those patients,” Dr. Duma said.
Researchers also found that only 36 percent of patients were aged 65 and older, even though cancer risk increases dramatically with age.
Finally, women were underrepresented in clinical trials for melanoma (just 35 percent), lung cancer (39 percent), and pancreatic cancer (40 percent).
RELATED: Why Black People Are Underrepresented in Clinical Trials
Not including these folks in clinical trials means that doctors are not fully equipped to treat all the various types of cancer that can strike different groups, said Christopher Li, MD, PhD, a research professor of epidemiology with Fred Hutchinson Cancer Research Center in Seattle.
“If these populations are underrepresented in clinical trials, there will also be an underrepresentation of the types of cancer that we know disproportionately affect them,” Dr. Li said. For example, Black and Hispanic women are much more likely to be diagnosed with aggressive breast cancer.
“Therefore, we will have less knowledge around the effectiveness of treatment that might be specific for these different forms of the disease,” Dr. Li continued.
Dr. Duma said research already has revealed some differences:
America’s history of unethical experimentation on minority groups prompts many to avoid participation in clinical trials, particularly Blacks, Dr. Duma and Dr. Li said.
They cited the Tuskegee Study, started in 1932, in which Black men were denied treatment for syphilis over four decades so researchers could observe the long-term effects of the venereal disease.
“Our country is still living with the legacy of things like Tuskegee,” Dr. Li said. He noted that fears about being involved in research keep some people from participating in clinical trials.
RELATED: Black People Have the Most Distrust of Clinical Research — Here’s Why
To address these concerns, clinical trial leaders need to expand access to their studies through community-based hospitals, rather than the collegiate research hospitals where most trials are conducted, Dr. Li said.
Researchers also should recruit spokespeople from various racial and ethnic groups “who have participated in research trials and can talk with other members of their community in ways they can trust,” Dr. Li added.
Dr. Duma said clinical trials could better support elderly participants — perhaps by helping them keep their medications organized and providing money to those living on a fixed income.
And medical journals can promote diversity by refusing to publish trials unless researchers provide tables showing the race, age, and sex of all participants, along with reasons why certain groups are underrepresented, Dr. Duma said.
For more information about clinical trials, visit BlackDoctor’s Clinical Trials Resource Center.
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