Abstract PO3-10-02: Cardiovascular Risk Factors and Outcomes in Native Americans who have Received Chemotherapy and/or Radiation: A Retrospective Single-center Study
Authors: Kirby Conor , Meyer-Hagen Jewel , Andre Paul , Khan Umair , Harris Nicholas , Davila Eduardo , Garcia Mark , Nemunaitis Jacklyn 
Published: May 2024

Introduction: There is scarce literature regarding cardiovascular risk factors and cardiovascular outcomes in Native American patients with breast cancer. Cardiovascular complications are known to be associated with cancer treatment. Certain medications, such as anthracyclines and HER-2 agents are directly cardiotoxic, while other modalities of treatment may lead to accelerated atherosclerosis. We have conducted a single-center retrospective study assessing cardiovascular risk factors and outcomes in Native American patients with breast cancer. Methods: Data was extracted from the UNM Comprehensive Cancer Center tumor registry and PowerChart. Charts were selected based on if the patient was registered as a Native American with a breast cancer diagnosis from 2010-2020. Inclusion criteria were age 18 or older, identified as Native American, received a diagnosis of breast cancer between 2010-2020, received at least one chemotherapeutic agent, endocrine therapy, or radiation therapy. Results: The study included 89 participants. The median age at the time of diagnosis of breast cancer was 55 years. All were female. Cardiovascular risk factors prior to undergoing treatment were reported as follows: Hypertension (55.3%); diabetes (46.1%); hyperlipidemia (35.3%); smoking (25%); obesity (52.6%). Before initiating treatment, 3.5% of Native American breast cancer patients in our study population had coronary artery disease.

Cardiovascular disease incidence before and after undergoing treatment was as follows: myocardial infarction (1.2% vs 2.4%), stroke (4.7% vs 1.2%), heart failure with reduced ejection fraction (HFrEF) (2.3% vs 4.8%), heart failure with preserved ejection fraction (HFpEF) (1.2% vs 1.2%), peripheral arterial disease (1.2% vs 1.2%), atrial fibrillation or another arrhythmia (4.7% vs 5.9%). We also noted new diagnoses of hypertension and arrhythmia in 3.6% and 1.2% of our study patient population respectively after starting chemotherapy.

43% of all included patients had a transthoracic echocardiogram (TTE) or multigated acquisition scan (MUGA) recorded in the chart before chemotherapy and 45% had one afterward. Of those, when comparing ejection fraction between pre- and post-chemotherapy, a change in mean EF (61.9% vs 57.8%) was seen.

37 patients (41.6%) received treatment with an anthracycline or a Her-2 agent. Mean EF prior to treatment was 65.0%, and mean EF after treatment was 59.1%. Pre- and post-treatment rates of HFrEF were 0% and 5.7%, respectively. Discussion: Hypertension, diabetes, hyperlipidemia, smoking, and obesity are highly prevalent in the Native American patient population who are treated for a diagnosis of breast cancer. Our study showed a change in mean EF after treatment (61.9% vs. 57.8%) in our Native American breast cancer patient population. For those receiving an anthracycline or Her-2 agent, EF changed from 65.0% to 59.1% after treatment. High rates of HFrEF, new onset hypertension, and arrhythmias post-treatment were also noted. These findings suggest that a thorough cardiovascular risk assessment prior to starting a treatment regimen for breast cancer may be important. Multidisciplinary management with cardiology may be critical in the care for these patients. Further investigation of cardiovascular risk factors and outcomes after cancer treatment is warranted in this population. There are several limitations of our study, one being that this was a single-center study which does not represent the Native American population throughout the United States and Canada. The small sample size also limits the power of the study. Many patients after initial evaluation at our facility received care at outside facilities, which limits data on treatments received, studies performed (e.g. TTE and MUGA), or cardiovascular events.

Citation Format: Conor Kirby, Jewel Meyer-Hagen, Paul Andre, Umair Khan, Nicholas Harris, Eduardo Davila, Mark Garcia, Jacklyn Nemunaitis. Cardiovascular Risk Factors and Outcomes in Native Americans who have Received Chemotherapy and/or Radiation: A Retrospective Single-center Study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-10-02.