Clinical trials test new ways of preventing, screening, diagnosing, or treating a disease. Black females are less likely than white females to participate in clinical trials for breast cancer, despite having a higher risk of aggressive forms of the disease.

The American Cancer Society (ACS) estimates that in 2022, approximately 339,250 females in the United States will receive a new diagnosis of breast cancer.

At every age, Black females are more likely than those belonging to any other racial or ethnic group to die from breast cancer. Compared with white females, Black females are 40% more likely to die of the disease.

This is partly because Black females with breast cancer tend to receive a diagnosis at a later stage. They are more likely to develop aggressive forms of breast cancer that are challenging to treat, including hormone receptor-negative and triple-negative breast cancers.

People of Color are also among those facing disparities in breast cancer research. For instance, Black females are less likely than white females to participate in clinical trials for breast cancer. This can affect the outlook for this population, as it means that scientists have less understanding of the types of breast cancers that affect Black females and of other factors unique to them.

This article looks at why Black females are less likely to be enrolled in breast cancer clinical trials. It also considers possible ways to address disparities in breast cancer research.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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According to a joint research statement from the American Society of Clinical Oncology (ASCO) and the Association of Community Cancer Centers (ACCC), only 2–8% of adults with cancer take part in clinical trials. Those who participate in trials tend to be younger, healthier, and less racially and ethnically diverse than people who receive cancer treatment outside of trials.

Overall, Black people represent 15% of people with cancer in the U.S. but only 4–6% of those who participate in clinical trials for cancer treatments. Hispanic people represent 13% of people with cancer but only 3–6% of trial participants.

In a 2021 study in JCO Oncology Practice, researchers reviewed 12 clinical trials on oral chemotherapy agents for breast cancer. Two-thirds of the trials reported the participants’ race or ethnicity. Across those trials:

  • 75.7% of participants were non-Hispanic white
  • 15.5% were Asian
  • 2.1% were Black
  • 3.7% were Hispanic

Multiple factors may contribute to the underrepresentation of People of Color in breast cancer trials.

Lack of referrals

Clinical trial participants often learn about these studies from their doctors.

According to the ASCO/ACCC joint research statement, biases influence which people doctors refer to clinical trials.

Some doctors might assume that Black people are unwilling to enroll in cancer trials or unlikely to follow the study protocols. They may not tell those individuals about available trials or invite them to participate.

If someone does not speak the same language as the doctor, the costs of translating clinical trial information and the time it takes may pose additional barriers to the doctor sharing that information.

Doctors themselves may be unaware of available trials. They may have limited time and resources to learn about trials and share that information with people who might benefit from them. These barriers may be more significant for doctors who work at hospitals or other centers that serve underrepresented racial and ethnic minority groups.

Medical distrust

Even when they learn about clinical trials, some People of Color may be reluctant to participate due to concerns about the study or the wider medical system.

People of any race or ethnicity may feel discomfort regarding the uncertainty of clinical trials. Experimental treatments in clinical trials may carry not only benefits but also risks of unknown side effects, which might be worse than the side effects of standard cancer treatments.

In double-blind clinical trials, participants may not know whether they are receiving the experimental treatment rather than a standard cancer treatment or a placebo. If a participant receives the experimental treatment, they do not know whether it will work.

If someone distrusts the medical system in general, this may contribute to their reluctance to participate in clinical trials.

According to a 2021 review in ecancermedicalscience, multiple studies have found reasons for lower rates of participation in cancer clinical trials among African American people. These reasons include:

  • poor trust in the biomedical research system
  • healthcare professional-related barriers
  • influence from family members
  • socioeconomic status
  • health literacy
  • spirituality or religious beliefs

This may reflect the history of medical racism in the U.S., which includes discriminatory research trials such as the 1932–1972 Tuskegee Syphilis Study. In this trial, researchers intentionally withheld treatment from Black males with syphilis to learn how the condition would affect them.

If someone experiences bias or discrimination from their primary care physician or other healthcare professionals, this may also contribute to medical distrust.

Restrictive eligibility criteria

Clinical trials only accept people who meet certain eligibility criteria.

According to the ASCO/ACCC joint research statement, cancer trials often exclude people with preexisting health conditions such as type 2 diabetes or heart disease.

People of Color are more likely than white people to have these conditions.

Financial barriers

Inadequate insurance coverage and other financial barriers may also prevent some Black females and others from participating in breast cancer research.

A 2016 study in JAMA Oncology found that people with a lower income were less likely than those with a higher income to participate in cancer trials. Due to systemic racism, Black and Hispanic Americans are more likely than white Americans to have lower incomes.

Trial sponsors typically pay for the cost of medications, procedures, or tests included in the study. However, they do not usually cover the costs of routine cancer care that someone may need while participating in a study.

Research in Health Affairs notes that Black and Hispanic Americans are less likely than white Americans to have insurance coverage, which can make it harder to manage the costs of routine care.

Clinical trial participants may also face travel-related expenses, such as transportation and lodging costs. They may need to take time off work or away from caregiving responsibilities to attend clinical trial appointments. People with a lower income may find it challenging to afford the loss of income or the cost of child care.

Racial and ethnic diversity in breast cancer clinical trials may help researchers understand the effects of socioeconomic disparities, gaps in healthcare access, genetic differences, and other factors that may account for negative breast cancer outcomes among Black females.

Certain treatments for breast cancer may also affect people of different races and ethnicities in different ways. Improving diversity in trials may help scientists understand those differences and ensure that treatments are safe and effective for everyone.

Clinical trials can also give Black females access to cutting-edge treatments that they cannot receive elsewhere.

To improve access to breast cancer clinical trials, the ASCO/ACCC joint research statement emphasizes the importance of collaboration among trial sponsors, researchers, clinicians, patients, patient advocacy groups, community leaders, and organizations.

The authors note that it is important for clinical trial researchers and referring clinicians to develop a good rapport with the people they serve, including Black females. They should let diverse community members know about clinical trials without assuming that certain groups will not be interested.

Targeted training may help researchers and clinicians recognize the importance of diversity in clinical trials, understand and address their own biases, and communicate effectively with diverse community members.

Engaging patient advocates, support groups, faith-based organizations, and other community groups in outreach efforts may also help raise awareness and increase enrollment in clinical trials among those currently underrepresented.

Increasing diversity among cancer researchers and healthcare professionals is also important. The ASCO/ACCC statement reports that people from traditionally marginalized populations are more likely to participate in clinical trials at centers with diverse workforces.

Providing flexible appointment times, parking vouchers, information in multiple languages, and other practical support may also help people overcome barriers to participating in trials.

How to overcome barriers

In some cases, people with breast cancer may be able to take steps themselves to overcome barriers to participating in clinical trials.

First, it is important for people with breast cancer to learn about clinical trials that might be a good fit for them. They can speak with a doctor or contact cancer centers to learn about available trials, including the potential benefits, risks, and costs of participating.

People may also find information about clinical trials online at:

If the time commitment or financial costs of traveling to clinical trial appointments pose a barrier to participation, it may help to speak with the clinical trial team or a patient navigator at the clinical trial site.

The clinical trial team may be able to conduct aspects of the trial by phone or online to limit the number of in-person appointments. Similarly, participants may be able to undergo blood work or other medical tests at a location closer to home to cut down on travel.

The clinical trial team might offer parking vouchers or other resources to help cover the costs of attending in-person visits.

They may also know of other community programs or organizations that help people manage the costs of cancer care and clinical trial participation. For example, a person might be eligible for support from the following organizations:

If a person has health insurance, they can contact their insurance provider to learn whether their plan covers any routine cancer care costs for which the trial sponsors are not paying.

When applying for a clinical trial, people typically need to:

  • submit a copy of their medical records
  • provide their informed consent to participate
  • complete surveys, medical tests, or both to ensure that they meet the eligibility criteria

During the informed consent process, people have an opportunity to learn about the potential benefits, risks, and costs of participating in the trial before they decide whether to enroll.

After applying, it may take several weeks for a person to learn whether the clinical trial team has accepted them onto the trial.

If they do not meet the eligibility criteria, they can ask the clinical trial team whether there are other trials that may be more suitable.

If they do meet the eligibility criteria, they might need to stop or adjust their current treatments before they begin participating in the trial. Their medical team can help them make these changes safely.

Different clinical trials involve different treatments, procedures, and tests. A person can learn what the trial will involve by speaking with the clinical trial team. They should ask about the frequency and length of the appointments and what they will involve.

Some people develop side effects from treatments in clinical trials. The clinical trial team can help a person learn about potential side effects and what to do if they develop them.

Participants have a right to leave clinical trials at any time.

The underrepresentation of people belonging to historically marginalized groups in breast cancer trials may contribute to disparities in health outcomes.

A lack of awareness of clinical trials, distrust of the medical system, financial barriers, and other factors may pose barriers to participating in clinical trials.

Collaboration among trial sponsors, researchers, clinicians, patients, community leaders, and organizations is necessary to address those barriers.

People with breast cancer can speak with a doctor, contact cancer care centers, and conduct research online to learn about available clinical trials. In some cases, clinical trial teams may be able to offer financial support or other assistance to help people overcome barriers to participation. Multiple organizations also offer support for travel, lodging, and other treatment- and trial-related expenses.