ATLANTA -- Many ethnic minority groups and elderly Americans are underrepresented in cancer clinical trials, according to results of a study presented at the 10th AACR Conference on The Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held here Sept. 25-28.
"Clinical trials are crucial in studying the effectiveness of new drugs and ultimately bringing them to the market to benefit patients," said the study's lead author, Narjust Duma, MD, a hematology/oncology fellow at the Mayo Clinic in Rochester, Minnesota. "However, many clinical trials lack appropriate representation of certain patient populations. As a result, the findings of a clinical trial might not be generalizable to all patients."
Duma and colleagues analyzed enrollment data from all cancer therapeutic trials reported as completed in clinicaltrials.gov, a database of publicly and privately supported clinical trials, from 2003 to 2016. From a pool of 55,689 enrollees, the study showed that 83 percent were white, 6 percent were African-American, 5.3 percent were Asian, 2.6 percent were Hispanic, and 2.4 percent were classified as "other."
African-American and Hispanic representation declined when compared with historical data from 1996 to 2002. In the 1996-2002 period, Duma said, African-Americans represented 9.2 percent of the patients in clinical trials and Hispanics represented 3.1 percent.
Also, Duma's study showed that patients age 65 and older represented 36 percent of the patients enrolled in clinical trials. Previous research has shown that the elderly are often underrepresented in clinical trials, despite the fact that most cancer cases are diagnosed in those age 65 and older, according to the National Cancer Institute's Surveillance, Epidemiology and End Results database.
Duma said the increasing use of genetic information in clinical trials may be depressing the numbers of ethnic minorities and elderly patients. In recent years, many trials have sought to study drugs that treat cancer by targeting certain genetic mutations. In order to identify the patients who are most likely to respond to the drugs, many clinical trials now require molecular testing of tumors, Duma explained.
"This is leading to significant advances; however, it is vastly more expensive to run these trials, often leaving a limited budget to recruit patients or do outreach to the elderly or minorities," Duma said. "Also, this type of testing can only be conducted at the major cancer centers. The midsized, regional hospitals are excluded because they don't have the capacity and, sadly, this leaves us farther away from these populations," Duma said.
Cultural biases may also make minorities less likely to enroll in clinical trials, Duma said. Previous research has shown that members of certain minority groups may be less likely to trust health care providers. Language barriers may also be a factor for minority patients, and the elderly may be dissuaded by difficulty in traveling to and from major cancer centers, she added.
Duma identified several potential ways to narrow the gap of participation in clinical trials:
- Increase clinical trial partnerships between major cancer centers and satellite hospitals. Duma suggested that patients could be enrolled at their local hospital, and undergo treatment there, while data could be sent to the partnering cancer center.
- Targeted interventions, such as Spanish interpreters, could be used to help enroll minority patients in clinical trials.
- Health care providers should be mindful of the need to enroll more patients from underrepresented populations, and should be willing to discuss risks and benefits with patients.
Duma said the main limitation of the study is that race and ethnicity are generally self-reported, which could lead to some inconsistencies in data.
This study was internally funded by the Mayo Clinic. Duma declares no conflicts of interest.
Representation of minorities, the elderly and women in over 1000 clinical trials.. Narjust Duma, Jesus Vera-Aguilera, Yucai Wang, Jonas Paludo, Konstantinos Leventakos, Aaron Mansfield, Alex Adjei. Mayo Clinic, Rochester, MN.
Background: Despite the importance of diversity while studying new drugs many cancer clinical trials (CT) lack appropriate representation of specific patients populations, limiting the generalizability of the evidence obtained. Therefore, we determined the representation of ethnic minorities, the elderly and women in cancer CT.
Methods: Enrollment data from all therapeutic trials reported as completed in clinicaltrial.gov from 2003 to 2016 were analyzed. CT in rare cancers (< 1% incidence) or with recruitment outside of the United States were excluded. Enrollment fraction (EF) was defined as the number of enrollees divided by the 2013 Surveillance Epidemiology and End Results (SEER) database cancer prevalence.
Results: Out of 1,012 CT, 310 (31%) reported ethnicity with a total of 55689 enrollees. 46431 (83%) enrollees were non-Hispanic white, 3270 (6%) African American, 2982 (5.3%) Asian, 1484 (2.6%) Hispanic and 1332 (2.4%) were classified as other. Participation in CT varied significantly across ethnic groups, non-Hispanic whites were more likely to be enrolled in CT (EF of 1.2%) than African Americans (EF of 0.7%, p <0.001) and Hispanics (EF of 0.4%, p <0.001). A decrease in African Americans (6% vs. 9.2%) and Hispanics (2.6% vs. 3.1%) enrollment was observed when compared with historical data from 1996 to 2002. Asians were well represented and their recruitment doubled over the past 14 years (2% vs. 5.3%). Hispanics were less represented in breast and prostate cancer CT only contributing to 3% and 1.5% of the study population. African Americans were less represented in lung (5.4%) and renal cell carcinoma (3%) trials. Enrollees' median age was 60 years with 64% of patients <65 years of age. Younger patients (<65 years) were more likely to be enrolled in CT than the elderly (64% vs. 36%, p < 0.001). Lower recruitment of female patients was observed in CT for melanoma (35%), lung (39%), and pancreatic cancer (40%).
Conclusions: African Americans, Hispanics and the elderly were less likely to be enrolled in CT. Comparing with historical data; we observed a decrease in minorities' recruitment over the past 14 years. This change could be attributed to the increased complexity of CT and mandatory molecular testing as many minorities lack access to institutions with genetic testing capacity. Future trials should take extra measures to recruit participants that adequately represent the US cancer population.
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