The study, published in JAMA Network Open, found those with advanced breast cancer at diagnosis were 10% more likely to have had pre-existing CVD. Additionally, the data revealed patients with a specific breast cancer subtype, hormone receptor-positive (HR+) and HER2-negative (HER2-), were most likely to have pre-existing CVD (11%).

“Cardiovascular disease can induce an immunosuppressive state, potentially fostering accelerated breast tumor cell growth and spread,” said senior author Kevin Nead, M.D., assistant professor of Epidemiology and Radiation Oncology. “Our findings suggest that women with cardiovascular disease may be more likely to be diagnosed with advanced breast cancer, highlighting a potential connection between the two.”

The case-control study looked at data from more than 19,000 individuals with a median age of 73 and compared the presence of CVD between patients with early (stage I-II) and advanced cancer (stage III-IV). The increased risk was present both for patients with locally advanced and metastatic breast cancer.

According to the National Cancer Institute, HR+/HER2− breast cancer constitutes nearly 70% of all breast cancer cases. When caught at an early stage, before it metastasizes, the disease is very treatable. However, the five-year relative survival rate for metastatic HR+/ HER2- breast cancer is only 34%, underscoring the need for prevention and early detection.

Cardiovascular disease is the cause of nearly one million deaths in the U.S. annually. This class of conditions can include coronary heart disease, stroke, high blood pressure, heart failure, hypertension and arterial disease.

Of those individuals included in the study, 49% were found to have CVD. The cohort was pulled from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked databases from 2009-2020. The analysis was completed from May 2023 to August 2024.

“The study could help inform personalized screening strategies, as it suggests that individuals with CVD may benefit from earlier or more frequent breast cancer screenings to catch the disease at an earlier, more treatable stage,” Nead said.

Limitations of the study include the fact that it was observational and does not demonstrate causality, susceptibility to residual bias, potential for misclassification of CVD, and lack of control for potential compounding factors, including smoking. The cohort was primarily white, which may also impact the generalizability of the findings.

This research was supported by the National Institutes of Health (CCSG P30 CA016672), the Cancer Prevention and Research Institute of Texas (CPRIT) (RR190077), and the National Cancer Institute (L30CA253796 and K08CA263313). A full list of collaborating authors and their disclosures can be found here.