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A senior, female breast cancer survivor takes her own blood pressure.

The link between breast cancer and heart conditions

Posted in: Blogs

There are many options for treating breast cancer, including breast cancer surgery, radiation therapy, chemotherapy, hormone therapy, and more. And while treatment is often necessary, research suggests that certain therapies for breast cancer can increase a patient’s risk of heart disease in the future. Let’s look into how breast cancer treatments can affect the cardiovascular system.

What effects can estrogen-based hormone therapy have in women’s cardiovascular systems?

Some tumor growths are dependent on hormones. If your lab results show estrogen-positive (ER+) and progesterone-positive (PR+) tumors, your doctor may recommend hormone therapy as a treatment to prevent the growth, spread, and recurrence of breast cancer. Having ER+ or PR+ tumors means that remaining cancer cells will continue to grow in the presence of these hormones in your body. Hormone replacement therapy (HRT) will block your body’s natural production of either estrogen or progesterone to help prevent the growth of ER+ and PR+ tumors.

While previous research has shown that HRT can reduce heart disease in women over 40, new studies suggest that the opposite may be true. Studies on the long-term use of HRT in women indicate that while it might decrease a woman’s susceptibility to osteoporosis later in life, it may also cause a higher risk of heart attack, stroke, and other serious health problems. 

Currently, the understanding of estrogen-based HRT in the treatment of older women is still being developed. What we do know is a mix of positive and negative effects. It: 

  • Relaxes and dilates blood vessels to increase blood flow
  • Increases HDL cholesterol (good cholesterol)
  • Decreases LDL cholesterol (bad cholesterol) 
  • Helps remove naturally occurring particles in the blood that can harm arteries
  • Can promote the growth of blood clots

Is there a link between chemotherapy, radiation therapy, and heart failure?

Recent studies have suggested a link between chemotherapy, radiation therapy, and cardiotoxicity. Chemotherapy and radiation therapy are two of the more well-known treatments for cancer. Radiation therapy includes targeted and precise radiation of cancerous areas in the body, and chemotherapy is the use of medication to stop the growth and development of cancer cells. A growing field of research into the long-term effects of cancer treatment is beginning to find a link between chemotherapy, radiation therapy, and congestive heart failure.

With improvements in cancer treatment, cancer patients live longer, giving way to long-term side effects from treatments as they get older. Certain medications used in chemotherapy might contribute to the development of heart failure, also known as cardiotoxicity, in the years after cancer treatment. The use of radiation therapy to treat breast cancer can also increase risks of heart failure due to radiation being directed at cancer growing in the chest area. 

Some studies have found that within five years of recovery, heart failure becomes three times more likely in people who received treatment for breast cancer or lymphoma than in people without a history of cancer treatment. Additionally, the age at which you received cancer treatment can increase your likelihood of heart failure even more. People who are treated for breast cancer or lymphoma who are 80 years of age or older have a greater risk of congestive heart failure than those who were treated at a younger age. 

A story close to home

The link between breast cancer treatment and congestive heart failure is not only defined by statistics and probability, but by the way it affects people’s quality of life. Cyndi Loper, a patient at Baylor St. Luke’s Medical Center and the Texas Heart® Institute, is one such person. 

In 1997, Loper was treated for breast cancer. She underwent rounds of radiation to her chest, and while it did treat her breast cancer, it had unfortunate consequences for her heart’s health. Seventeen years after her initial breast cancer treatment, Loper was evaluated for a complete heart transplant at Baylor St. Luke’s Medical Center and Texas Heart® Institute; however, due to her complex situation, she didn’t qualify for a transplant. 

It was after her rejection for a heart transplant that she first visited Baylor St. Luke’s Heart Failure Clinic and found Dr. Reynolds Delgado III, a cardiologist specializing in heart failure and heart transplantation—her new cardiologist. 

Despite her challenging case, the physicians at Baylor St. Luke’s Heart Failure Clinic worked with what options were available. They not only monitored the fluid around her heart and provided tips on living a healthy lifestyle, but they took the time to help her understand her vital signs in relation to her medications. They were able to develop a personalized treatment plan for Loper, giving her hope for the future. 

According to Loper: “The diagnosis was dreary, but the outcome has been fabulous. No one thought I would still be here four years later. There wasn’t much other hospitals and specialists could do for me, but Dr. Delgado III and the team at Baylor St. Luke’s have given me a new beginning.” 

Who is at a higher risk of congestive heart failure after breast cancer treatment?

Breast cancer patients who have any of the following risk factors are at an increased risk of congestive heart failure.

  • History of smoking
  • History of heart failure
  • History of diabetes 
  • An inactive lifestyle
  • People who receive treatment for cancer at 80 years of age or older

Our health system has dedicated oncology and cardiology teams who work collaboratively with their patients to provide innovative and personalized care options. Baylor St. Luke’s Medical Center is nationally ranked for cancer care and for cardiology and heart surgery. 

The Dan L Duncan Comprehensive Cancer Center is known for its breakthrough scientific research and is distinguished as one of the best cancer treatment centers in Texas. Our medical partnership with Baylor College of Medicine gives our patients access to one of the largest clinical genetics research programs in the nation. If you are in the Greater Houston area and have been diagnosed with cancer, schedule an appointment with one of our oncologists to benefit from our advanced oncology services at Baylor St. Luke’s Medical Center or at the Dan L Duncan Comprehensive Cancer Center at The Woodlands Hospital.

In cardiology and heart surgery, Baylor St. Luke’s Medical Center is nationally ranked by U.S News & World Report. From the first transplant of an artificial heart into a human to treating a variety of complex heart conditions, our team of cardiologists use both compassionate and comprehensive care to provide hope to patients from all over the world. Should you be struggling with heart failure post-cancer treatment or have other cardiovascular concerns, consider making an appointment with one of our cardiologists who can provide you with the care you need.

Cancer care in East Texas

For nearly 60 years, the Temple Cancer Center at St. Luke’s Health-Memorial in Lufkin has delivered advanced cancer treatment and research. This cancer center boasts innovative techniques and collaborative care with St. Luke’s Health-Memorial to give patients all the tools they need to help them improve their health during and after cancer treatment.

All of our Baylor St. Luke’s Medical Group cardiologists at St. Luke’s Health-Memorial are board-certified and specialize in all aspects of cardiovascular care, from disease prevention to rehabilitation post-treatment or surgery. Whether you have high blood pressure or are experiencing heart disease after cancer treatment, our cardiologists will be able to provide a personalized treatment plan for you. 


Baylor College of Medicine | Breast Cancer Treatment Options
National Cancer Institute | BRCA Gene Mutations: Cancer Risk and Genetic Testing
ABC13 | 2 Families Connected By 1 Heart
National Cancer Institute | Higher Risk of Heart Failure Seen in Some Cancers
Cleveland Clinic | Cardiotoxicity: Cancer Treatment & the Heart
Cleveland Clinic | Estrogen & Hormones
US National Library of Medicine + National Institutes of Health | Hormone replacement therapy: dilemmas in 2002.

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