The Link Between Breast Cancer and Heart Disease in Women

A recently published study suggests that older women with cardiovascular disease (CVD) are diagnosed with more advanced breast cancer, a link that may change how both cardiologists and oncologists screen their patients and collaborate in their care. Experts at Sylvester Comprehensive Cancer Center and the University of Miami Health System hope the research will result in “more integrated care.”

Claudia Martinez, M.D., a interventional cardiologist and physician-scientist who cares for women with heart disease, noted that this study underscores a growing body of research linking the two diseases in a “bidirectional way.”

Heart disease may increase the risk of advanced breast cancer, and advanced breast cancer is linked to a higher risk of heart disease.

“I hope this leads to a more team-based approach in the clinical setting,” says Dr. Martinez. “It also opens the possibility of the two [disciplines] working together. For me, it is a reminder that we must tell our patients to continue their regular screenings in addition to caring for their heart health.”

These research results, she adds, should also prompt women with cardiovascular issues to have mammograms sooner and more frequently in order to diagnose the disease at an earlier stage, which, in turn, can make the cancer more treatable.

As patients, knowing the risk factors for CVD and breast cancer is essential.

Understanding that by not addressing them, you increase your risk not only for CVD but also for more advanced breast cancer at diagnosis is vital. On the flip side, implementing lifestyle changes and CVD risk reduction strategies decreases your risk for both diseases.

Carmen Calfa, M.D., a breast medical oncologist at Sylvester Comprehensive Cancer Center, part of UHealth, agrees the information from the study offers an opening for a renewed look at risk assessment and risk reduction strategies.

“We have an opportunity to decrease the risk of developing and dying from both diseases, the CVD as well as the breast cancer. And that’s what I think is the most important lesson to be learned here and the mission to collectively take on.  I believe that knowledge and awareness can empower us all.”

The study, published in JAMA Network Open, looked at health data for almost 20,000 breast cancer patients who were at least 66 years old.

Those with advanced cancer — both metastatic and locally advanced — were 10% more likely to have heart disease than those with tumors diagnosed in the early stage. The degree of risk depended on the type of tumor. For example, patients who had metastatic disease (cancer that had spread to other parts of the body) were at a 20% higher risk of also having heart disease. That risk dropped significantly, to 9%, for those with locally advanced breast tumors or cancer that has spread into lymph nodes and surrounding tissue.

Risk was also influenced by the type of breast cancer and the stage of the cancer. Hormone receptor-positive tumors (HR+) and HER2-negative cancers are the most common type of breast cancer, accounting for about 70% of all cases, according to the National Cancer Institute. The NCI also showed the strongest association with heart disease (HR+ tumors are positive for estrogen and/or progesterone, which fuel the growth of cancer, and HER2- tumors have a protein that helps breast cancer cells grow quickly.)

Older studies support the growing body of research that is underpinning the newer discipline of cardio-oncology, which seeks to treat and prevent the elevated risk of heart disease in patients after cancer treatment. One 2011 study found that cardiovascular disease was a significant cause of mortality — almost as much as the cancer itself — for older women diagnosed with breast cancer. Another, in 2019, reviewed the cardiovascular risks associated with breast cancer treatments and recommended a multi-disciplinary approach to managing cardiovascular health in breast cancer patients.

At Sylvester and UHealth, clinicians are already pioneering this care.

“To me, cardio-oncology is the discipline that is mindful of preserving the heart function while delivering the best cancer treatment, with the focus on the overall well-being of the patient in front of us,” Dr. Calfa says. “At Sylvester, our survivorship program focuses on the ongoing cardio-oncology evaluation of our patients while maximizing lifestyle and minimizing risk factors for CVD. From working with the PCPs (primary care providers) to enhance awareness and access of all patients to gender-appropriate screening and management of all comorbidities, having specialty clinics that manage chemotherapy and immunotherapy side effects, to using proton therapy to spare the heart, our focus is on maximizing outcomes and minimizing downstream cardiovascular harm.”

Both diseases top the list of causes of death in the country.

• Heart disease, including stroke, heart failure, and hypertension, is responsible for about one million deaths in the U.S. annually.
• As for breast cancer, an estimated 42,250 U.S. women died from it in 2024.

Neither disease is a death warrant if caught and treated early. When HR+/HER2− cases are diagnosed before metastasis, there is a 99% five-year survival rate. However, when it spreads to distant parts of the body, the five-year survival rate drops to 34%. With CVD, the American Heart Association estimates that up to 80% of heart and stroke events could be prevented with lifestyle changes.

Researchers and cardiologists are not entirely sure why the two diseases are associated, but there are plenty of theories.

“Both cancer and cardiovascular disease share many of the same risk factors,” Dr. Martinez says.

Adds Dr. Calfa: “The good news is that many of those are modifiable, such as diet, exercise, smoking, drinking, high cholesterol, obesity, high blood pressure, etc.”

Smoking, for example, is a leading risk factor for both breast cancer and heart disease.

In addition, poor lifestyle choices also contribute to an increased likelihood of developing both diseases.

More recently, researchers have discovered a link between a cardiovascular event, such as a heart attack, and the more rapid growth of cancer cells. How does that happen? A CVD incident can suppress the immune system, making it harder for the body to break down abnormal cells. One showed that a heart attack may produce faster growth and spread of breast cancer cells than in those who do not suffer a heart attack.

In reverse, cancer patients might also develop heart problems after treatment. Chemotherapy and radiation therapy are known to cause cardiotoxicity, including arrhythmias, stroke, and heart failure. The prevalence of cardiotoxicity can develop soon after treatment or years later, and it varies depending on the type of treatment.

Dr. Martinez says more research needs to be done on the subject, particularly as it might relate to younger women. The JAMA Open Network study only examined post-menopausal women.

In the meantime, “we should focus on prevention methods and improving our lifestyles,” she adds. “Exercising, getting enough sleep, eating a healthy diet, not smoking and reducing stress are still important.”

Ana Veciana-Suárez is a regular contributor to the University of Miami Health System. She is an acclaimed author and journalist who has worked for The Miami Herald, The Miami News, and The Palm Beach Post.

Tags: breast cancer care, cardiovascular disease, Integrated healthcare, Sylvester Comprehensive Cancer Center, women and heart health