“We know that there are disparities – racial and ethnic, sex and gender, and socioeconomic – in morbidity and mortality in cancer survivors and people with cardiovascular disease,” says Rachel Ohman, MD, an Internal Medicine resident physician and future Chief Resident in the Department of Medicine at UCLA.
“What we don't understand well is how those disparities may interact and influence each other.”
Both cancer and cardiovascular disease are on the rise in the United States, Dr. Ohman says. Cardiovascular disease is the leading cause of death outside cancer in certain populations, including prostate cancer and breast cancer survivors.
An extensive body of research shows a disproportionate burden of both illnesses among Black patients, American Indian and Alaska Native patients, certain Asian and Pacific Islander patients, and certain Latinx patients as well as lower income communities and other minoritized populations, she says. (Minoritized refers to groups that face prejudice for demographics beyond their control.)
In addition, cancer outcomes may be intertwined with cardiovascular ones, preliminary evidence suggests. Patients with cancer may be at higher risk for cardiovascular-related adverse effects of treatment, particularly if they have pre-existing cardiovascular risk factors or known heart disease.
Preventing and managing cardiac disease among patients with cancer is the cornerstone of the rapidly growing multidisciplinary field of cardio-oncology, which focuses on cardiotoxicity, the cardiovascular toxicities from cancer therapies such as chemotherapy, novel targeted therapies (e.g., trastuzumab), immunotherapy and radiation therapy.
In a comprehensive review published in the Journal of the American Heart Association, Dr. Ohman together with Dr. Eric Yang, director and founder of the UCLA Cardio-Oncology Program, and Dr. Melissa Abel, a recent UCLA Internal Medicine residency graduate and current hematology and oncology fellow at the National Institutes of Health, examined the available scientific studies on disparities in cardiotoxicity. They interpreted those data in context of known disparities in cancer, known disparities in cardiac disease, and potential system-wide inequities in disease diagnosis, care, and treatment.
Dr. Ohman and her colleagues are sounding the alarms that more research is needed on outcome disparities in cardiotoxicity and the broader inequities that exist in cardio-oncology, as there are limited data connecting the disparities of cardiac and cancer care together.
“That’s why we felt that it was so important to do an extensive review of the literature,” she says, “to better understand what we know about disparities in cardio-oncology, specifically regarding cardiotoxicity of treatment.”
Cancer and cardiotoxicity
Cardiotoxicity is a condition in which different parts of the cardiovascular system, including the heart muscle, heart valves, blood vessels, and electrical conduction of muscle tissue, are damaged due to unintended, negative side effects of cancer treatment. This damage can have long-lasting effects during and even after treatment.
Cardiotoxicity during cancer treatments can also alter a patient’s treatment course by changing the outcome of potentially life-saving cancer therapies. This can lead to worsened survival and/or outcomes from cancer. Additionally, the effects of cancer itself can aggravate cardiovascular disease risk factors or pre-existing disease.
Any combination of these negative effects on the cardiovascular system can interfere with cancer recovery – and they are worse for some populations versus others.
In a Twitter thread summarizing the paper, Dr. Yang explained that Black patients with breast cancer are more likely to develop cardiotoxicity from cancer treatment and have higher risks of mortality related to cardiovascular disease in comparision to White counterparts.
Preliminary data also show that certain Asian and Pacific Islander subgroups with breast cancer have higher risks of mortality related to cardiovascular disease than White counterparts, demonstrating that the grouping of API patients together may mask disparities between API subgroups.
Also, “Data among adolescent and young adult survivors of cancer show that poverty, education level and geographic region are associated with higher risks of cardiovascular mortality,” Dr. Yang said in a tweet citing the recent review.
Ultimately, the studies analyzed in their review article lead to more questions than answers.
“Many of us, myself included, have studied cardio-oncology within this traditional paradigm of just reacting to and studying the cardiac side effects from cancer treatments when they happen,” he says, “but we need to think outside our comfort zone and look at the upstream societal factors.”
Barriers to care
The review authors discuss how the current data on cardiotoxicity disparities point to significant contributions from social determinants of health including broader forces of racism and sexism.
Additionally, they discuss how access to specialty care, differences in treatment costs, a lack of diverse representation in clinical studies, and patient distrust may also contribute to inequities.
“The question becomes ‘What are the influencing factors of risk before patients even get cancer?’ Or ‘What are the some of the barriers to cancer and heart care, that make them more vulnerable to heart complications during and after treatments?’” Dr. Yang says.
“How much are we, as an institution with our own biases plus societal or systematic biases towards certain groups, contributing to this problem?”
More research is needed, but there are some strategies that can be implemented right away to begin reducing disparities in cardio-oncology, say the authors of the review. These include:
- Giving access to comprehensive cardiac evaluations for all cancer patients with early referral to cardio-oncology specialists
- Developing strategies to better understand social and structural vulnerabilities
- Using equitable mobile and virtual care to overcome barriers to access
- Investigating how social determinants of health, implicit bias, racism, and sexism affect treatment outcomes
- Promoting inclusion and diversity in clinical trials
- Working with community groups and cultural institutions to improve awareness of cardiovascular and cancer screenings
- Training all healthcare workers to recognize implicit bias that may influence how they care for certain populations.
Learn more about and book an appointment with cardiology services at UCLA Health.
