Understanding the breast cancer-heart disease link

Research will help cancer survivors reduce their heart risk
Two senior women talking and drinking tea

There is a well established link between treatments for breast cancer and the onset of heart disease — both leading causes of death in Canada. However, little information exists about how the balance of these risks might affect any individual woman. 

Until now that is. Research overseen by Dr. Geoffrey Anderson and supported by Heart & Stroke donors has come up with some surprising and valuable insights into the link. The findings will help pave the way for women treated for breast cancer to avoid future heart failure.

Working with Dr. Anderson at the University of Toronto, cardiologist and PhD candidate Dr. Husam Abdel-Qadir undertook a comprehensive analysis of data from Ontario’s health insurance plan (OHIP) records covering 1998 to 2012.

“What we did,” says Dr. Abdel-Qadir, “is track the results of nearly 100,000 Ontario women over more than a decade. It is a genuinely representative sample from the real world.”

The results were both predictable and surprising. While it is well-recognized that many breast cancer patients receiving treatment experience some damage to the heart, it was not necessarily severe enough to cause hospitalization or death.

They discovered that the risk of dying from cardiovascular disease depends on the woman’s age at diagnosis as well as her history with cardiovascular disease. The older the patient, the greater the risk of dying from cardiovascular causes.

Dr Husam Abdel Qadir

It is a genuinely representative sample from the real world.

Dr. Husam Abdel-Qadir Heart & Stroke researcher

If you are older than 65 years when diagnosed with breast cancer, your risk of dying from heart disease becomes comparable to that from breast cancer after surviving five years past the cancer diagnosis.

For women under 65 with no history of heart disease, the likelihood of dying from heart disease is negligible in comparison with breast cancer.

Not surprisingly, it’s different for women who have established heart disease before their breast cancer. These women had a comparable risk of dying from cardiovascular causes and breast cancer for the first five years. After that, cardiovascular disease becomes their leading cause of death.

In another study, Dr. Abdel-Qadir examined how heart failure after breast cancer relates to other forms of cardiovascular disease. Heart failure in this setting is commonly thought to be a direct consequence of the cancer treatment. He discovered that most cases of heart failure that are severe enough to cause hospitalization only happen if a woman has a prior history of cardiovascular disease, or risk factors for it.

With this knowledge, doctors and breast cancer survivors both can pay greater attention to maintaining heart health rather than reducing cancer treatment. Through exercise, diet, lowering blood pressure and controlling cholesterol, breast cancer survivors may be able to reduce their risk of heart failure.

For his groundbreaking work, Dr. Abdel-Qadir received Young Investigator awards at two major conferences in Europe.