Cancer causes structural and mechanical changes in the heart

Research at the University of Calgary’s Cumming School of Medicine (CSM) has shown that some cancers cause structural and mechanical changes in the heart.

Dr. James White, MD, a clinician-researcher and the director of the Stephenson Cardiac Imaging Centre at Alberta Health Services' Foothills Medical Centre, led the largest and most comprehensive study to date on the impact of cancer on the heart. Using advanced magnetic resonance imaging (MRI) techniques, White and his team studied 381 individuals with recently diagnosed breast cancer or lymphoma and compared them with 102 healthy volunteers.

The study participants underwent comprehensive MRI scans which were used to create 3D models of their beating hearts and maps of inflammation markers, allowing researchers to assess the appearance and function of their hearts. The results, recently published in the Journal of the American Heart Association, were surprising.

“What we saw is that when you have cancer, your heart is smaller in size, beats faster and contracts differently,” says White, explaining the changes were most significant in the volume of the left ventricle, the chamber of the heart that provides oxygenated blood to the rest of the body and in how hard the heart was working to pump.  

We now know that when we are about to start treatments in people with cancer, we can’t assume that their cardiovascular system is in a normal state of health.

Cancer treatment has long been known to impact the heart. Cancer survivors are not only at higher risk of developing cardiovascular conditions, like heart attacks and strokes, but their hearts may also be damaged by cancer medications, a condition called cardiotoxicity, which can lead to heart failure.

Cardio-oncology is a relatively new field of medicine developed to treat cancer patients with cardiac injuries caused by chemotherapy, but until now there has been little investigation into the impact of cancer itself on the heart.

Study gives new insight 

Dr. Winson Cheung, MD, an oncologist and researcher at the CSM, says although the study was not aimed at immediately changing his clinical practice, it gives new insight into how cancer impacts the heart.  

“Because the majority of the work on the connection between cancer and the heart so far has studied the impact of chemotherapy and radiation on the heart, it is quite novel and informative to show evidence that cancer patients are different and have unique cardiac needs irrespective of their treatment,” says Cheung, co-investigator in the study. “The study gives us pause and suggests that prior to treatment, there is a need to evaluate the heart.”

Cancer is known to cause a systemic inflammatory state in the body that contributes to common cancer symptoms like weight loss and general unwellness. White said his findings support that this process may similarly affect the heart, their findings being consistent with heart inflammation.

Researchers also found some of the study participants had more severe changes to their heart. White’s hope is that the information will be used to identify those at higher risk of developing cardiotoxicity, heart injury due to cancer treatments, so care teams can alter treatments to reduce the risk of permanent damage to the heart.

Cheung agrees.

If we can identify individuals at risk, there may be a way to mitigate risk of worse outcome.

White’s research team will continue to study these patients for a decade to see the long-term effects of cancer treatment on the heart. He is hopeful that the changes seen in the hearts of cancer patients resolve after successful elimination of cancer from the body. It’s an important consideration, because nearly half of all Canadians will receive a cancer diagnosis in their lifetime.

Raja Mita, executive director of Health Innovation for Alberta Innovates, one of the study's funders, says technology is the future of health. 

“We believe that digital technologies will be a gamechanger in health," says Mita. "This is a really neat example of how complex 3D imaging models are accelerating clinical science in a meaningful way for patients."