The cancer–heart disease connection
Cancer survivors face a heightened risk of heart disease. The reverse — more cancer among people with heart disease — may also be true.
- Reviewed by Christopher P. Cannon, MD, Editor in Chief, Harvard Heart Letter; Editorial Advisory Board Member, Harvard Health Publishing
Thanks to advances in cancer detection and therapy, people with cancer are living far longer than in years past. Nearly 20 million people in the United States — about 6% of the population — are cancer survivors. "Despite what you might assume, these people are actually more likely to die of heart disease than from cancer-related complications," says Dr. Anju Nohria, director of the cardio-oncology program at Harvard-affiliated Dana-Farber Brigham Cancer Center.
One reason is that certain cancer treatments can cause cardiovascular complications (see "How cancer therapies may harm the heart"). But the two diseases share many root causes. For example, tobacco use is widely known to raise the risk of both heart disease and cancer. And some experts believe obesity (a known contributor to heart problems) may soon surpass cigarette smoking as the No. 1 preventable cause of cancer. Other health issues linked to heart disease — diabetes, high cholesterol, and high blood pressure — are also associated with cancer, as described in a review titled "Cardiovascular Disease and Cancer: A Dangerous Liaison" in the March 2025 issue of Arteriosclerosis, Thrombosis, and Vascular Biology.
The common threads
In people with diabetes, high blood sugar damages blood vessels and nerves that control your heart, increasing the risk of heart attack, stroke, and other cardiovascular problems. The resulting inflammation can also create an environment that favors tumor growth, and elevated blood sugar levels may help fuel the growth of malignant cells, Dr. Nohria explains. Likewise, excess blood cholesterol — a key component of artery-clogging plaque — may also hasten growth of cancer cells.
High blood pressure's role in heart disease is clear: the relentless pounding of the blood against the artery walls also promotes plaque formation, and the resulting narrowing of the arteries only worsens the problem. The observed connection between high blood pressure and cancer isn't as well understood, but it may arise from alterations in blood flow, increased inflammation, and other factors.
Finally, people who've had a heart attack or heart failure appear to develop cancer more frequently than the general population, recent studies suggest.
How cancer therapies may harm the heartThe risk of heart problems during or after cancer treatment depends on the type and amount of drugs or radiation you receive and how healthy your heart was before the treatment. Older chemotherapy drugs called anthracyclines, such as doxorubicin, which are used mainly to treat leukemia and lymphoma, can impair the heart's pumping ability. So can trastuzumab (Herceptin), a breast cancer therapy first approved in the late 1990s. More recently, many novel therapies that help the immune system recognize and attack cancer cells have been developed. One promising type, known as immune checkpoint inhibitors, could potentially be used to treat half of all cancers, says Dr. Anju Nohria, associate professor of medicine at Harvard Medical School. But sometimes, these drugs trigger an autoimmune reaction that attacks various organs, including the heart. In about 1% of cases, this leads to myocarditis (inflammation of the heart muscle), which is often mild but sometimes very serious. "What we don't yet know is whether the chronic, low-grade inflammation that these drugs cause might increase a person's future risk of heart attack and heart failure, as some preliminary studies suggest," says Dr. Nohria. |
If you have cancer or heart disease
If you're diagnosed with cancer, ask your doctor whether your planned treatment might lead to cardiovascular problems. This is especially important for people ages 65 and older and anyone with risk factors for heart disease (such as high blood pressure or diabetes), who may want to request a referral to a cardio-oncologist.
"When we see people who've undergone treatment for cancer, we try to identify and modify their risk factors for heart disease as much as possible," says Dr. Nohria. Many cancer survivors get CT scans as part of their treatment and surveillance. If these scans reveal calcium deposits in their coronary arteries, they may benefit from cholesterol-lowering drugs to limit their risk of a heart attack. Likewise, people with heart disease should be sure to follow cancer screening guidelines from the American Cancer Society.
People with serious health conditions sometimes adopt a fatalistic view and abandon healthy lifestyle efforts, says Dr. Nohria. Others view their diagnosis and recovery as a new lease on life and do everything they can to stay healthy — an approach she actively supports.
Image: © FatCamera/Getty Images
About the Author
Julie Corliss, Executive Editor, Harvard Heart Letter
About the Reviewer
Christopher P. Cannon, MD, Editor in Chief, Harvard Heart Letter; Editorial Advisory Board Member, Harvard Health Publishing
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