Cancer patients should be warned of heart risks

Cancer patients are not being advised by their physicians that there is an increased risk of cardiotoxicity associated with their treatments.

This is according to new Australian research which also found that many physicians are not fully aware of the dangers themselves.

“Depending on the type of chemotherapy and radiotherapy, between 1% and 25% of cancer patients may develop heart failure due to cancer treatment,” said study author Professor Robyn Clark, of Flinders University, Adelaide.

“Risk also depends on cardiovascular risk factors such as smoking and obesity. Better monitoring of the heart and intervention before, during and after treatment can prevent or lessen the impact of this cardiotoxicity.”

The researchers reviewed medical records of 46 randomly selected cancer patients with cardiotoxicity who attended one of three hospitals between 1979 and 2015. Just 11% were referred to a cardiologist before chemotherapy and less than half (48%) were referred to a heart failure clinic after cancer treatment. Almost 40% were overweight or obese, 41% were current or ex-smokers, 24% were regular consumers of alcohol, 48% had hypertension and 26% had diabetes — all of which can signal cardiovascular disease risk.

Cardiotoxicity is detected using electrocardiogram (ECG), cardiac imaging and biomarkers. The frequency of assessment depends on a number of factors — for example, evaluation for coronary artery disease, ischaemia and vascular disease is recommended in patients with a history of mediastinal radiation starting five years post-treatment and then at least every five years thereafter, even if they have no symptoms.

Angiotensin-converting enzyme (ACE) inhibitors or beta-blockers may be given to prevent or treat heart failure. And cancer therapy can be modified — for example, reducing the dose or having a gap between two agents which raise heart failure risk when taken together (eg, anthracyclines and trastuzumab).

“Monitoring the heart throughout the cancer journey can ensure it is protected,” said Professor Clark. “Cardiotoxicity can occur even in people without cardiovascular risk factors since drugs like anthracyclines and trastuzumab are toxic to the heart, so it is an innocent bystander.

“For cancer patients who do develop heart failure, there are clinics that will improve their quality of life but our study shows many are not referred,” she added. “Telephone calls to support and monitor those with cancer and heart failure would reduce the burden of hospital appointments, which patients said was a priority.”

The European Society of Cardiology (ESC) published recommendations in 2016¹ and in 2018 launched the ESC Council of Cardio-Oncology to promote the prevention, early diagnosis and management of cancer therapy-related cardiovascular diseases. The ESC believes patients should be told about the risks to their heart before starting cancer therapy; given help to quit smoking, eat healthily, exercise and control their weight; and be told to report signs and symptoms of cardiovascular disease.

Reference

1. Zamorano JL, Lancellotti P, Rodriguez Muñoz D, et al. 2016 ESC Position Paper on cancer treatments and cardiovascular toxicity developed under the auspices of the ESC Committee for Practice Guidelines. Eur Heart J. 2016;37:2768–2801. doi:10.1093/eurheartj/ehw211.

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