How cancer treatment can affect the heart

How does chemotherapy damage the heart?

There are certain treatments that can have a small risk of affecting the function of the heart. We are aware of these and test the heart before giving treatment. Understanding these effects, we have given lower doses of chemotherapy and followed the heart closely with repeat tests. We’ve also developed a new discipline called ‘cardio-oncology’ where oncologists work closely with cardiologists to decrease the risk of affecting the heart by treating cancer.

As current president of the Canadian Cardio-Oncology Network, our mission is to ‘cure cancer/save hearts’. When we see patients for the first time, we do a thorough assessment of their medications to ensure that patients are optimized for their treatment. For example, if a patient has had a significant history of heart disease, such as a previous heart attack, active chest pain or previous heart surgery, we tend to refer to cardio-oncology prior to starting treatment to ensure that the heart treatment is optimized and we mitigate any risk to the heart with our cancer treatment.

What symptoms or signs should patients watch for if their heart has been damaged due to treatment?

Signs of treatment affecting the heart can include shortness of breath, chest pain, heart palpitations, and ankle swelling. Anyone experiencing a new onset of these symptoms should speak with their treating oncologist and ensure that the heart is assessed, through an ECG (electrocardiogram), bloodwork specific to the heart, and an echocardiogram. If there seems to be an issue, then we will refer to a cardiologist, with some centres having dedicated cardio-oncology clinics.

Is heart damage from chemotherapy reversible?

Some treatments such as targeted antibody therapies can be reversible. Some other anti-cancer treatments can permanently affect the heart, but with new heart medications that work to control blood pressure, lifestyle modifications like improving cholesterol levels, we can improve heart function after cancer treatment.

What can patients do to get back on their feet and repair their heart after cancer treatment?

Aerobic exercise is always beneficial to the heart, and it is recommended to at least walk or run for 15 minutes every day to the point where you cannot speak in full sentences (you’re breathless). You can do this anywhere, even go to your local mall. There are many virtual apps that can also be used for strength training (no gym required) and gentle cardio.

Can heart damage due to chemotherapy be prevented? What do you recommend to patients just starting treatment?

That is a great question - cardiovascular disease and cancer share many 'risk factors' - obesity, alcohol, smoking. Therefore, improving these risk factors can help protect the heart. Also, I recommend patients work with their oncologist and if there are concerns or you have risk factors for cardiac complications, a referral to a cardiologist is recommended so that your heart can be optimized prior to starting anti-cancer therapy. These 'modifications' can be medications, exercise, or even changes to your anti-cancer treatments or some cardio-protective medications.