Chemotherapy and radiation used to treat cancers can help to prolong lives, but these treatments can also increase heart attack risk. The American Heart Association recently recommended that patients receiving chemotherapy or radiation to treat breast cancers should be made aware that these treatments increase heart attack risk and that all people being treated for cancer should be on a lifestyle program to prevent heart attacks (Circulation, February 1, 2018). The authors note that breast cancer survivors are more likely to die from heart attacks or heart failure than from the breast cancer itself.
Furthermore, many risk factors for cancers are also risk factors for heart attacks. For example, being overweight or having high blood sugar levels are major risk factors for recurrence after treatment for both breast cancer and prostate cancer as well as for heart attacks (American Association for Cancer Research meeting, Austin TX, Jan 26, 2018).
How Can Radiation or Chemotherapy Increase Heart Attack Risk?
Radiation, chemotherapy and hormone cancer treatments can help to kill cancer cells but can also increase risk for diabetes and high blood pressure that are associated with increased risk for heart damage (J of Clinical Oncology, January 18, 2018). Radiation can affect the heart arteries to cause heart attacks, or damage the heart muscle itself to cause heart failure (New Engl J of Med, March 14, 2017). The higher the radiation dose, the greater the risk of heart damage (J of Clin Onc, March 20, 2017). Signs of heart damage from radiation may not show up for years after treatment (Circulation, 2004;109:3122-3131), and can cause death 10 to 20 years later (Acta Oncol, Feb 2011;50(2):187–93).
Various chemotherapy treatments can weaken heart muscle to cause irregular heartbeats and heart failure, and can constrict heart arteries to cause chest pain and heart attacks. Cancer drugs called angiogenesis inhibitors can cause high blood pressure which increases heart attack risk.
If you are diagnosed with any type of cancer, be sure that your doctor explains to you all of the side effects associated with your proposed treatments, and strategies to minimize those side effects. You should be evaluated for heart attack risk factors such as high blood pressure, high cholesterol, and high blood sugar 1-hour (>140 mg/cc) after meals, and these risk factors should be monitored during and after your treatment. Start (or continue) a program to control these risk factors, with an anti-inflammatory lifestyle that includes:
• maintaining a healthful weight
• trying to exercise every day
• eating plenty of vegetables, whole fruits, beans, whole grains, nuts and other seeds
• restricting or avoiding sugared drinks, sugar-added foods, red meat, processed meats and fried foods
• avoiding smoke and alcohol
• keeping blood levels of hydroxy vitamin D above 20 ng/ml