Imagine being cured of cancer, only to learn the treatment that saved your life caused you to develop heart failure. Or perhaps your risk factors for heart disease spiral out of control when you begin chemotherapy. More concerning: What if your doctor suggests you stop your cancer treatment because it’s damaging your heart?
Cardiologists are not specialists in cancer drugs, and oncologists may have limited knowledge of treating heart disease and its risk factors. Yet many patients have both major diseases, and the drugs used to treat one can cause or affect the other.
Fortunately, recognition of the need to straddle both specialties has given rise to a new division of cardiology called cardio-oncology.
Hidden and Present Dangers. An estimated two-thirds to three-fourths of patients undergoing cancer treatment take drugs that increase cardiovascular risk. Anthracyclines are a prime example.
The toxic effects of these drugs used to treat breast and blood cancers are well known, and oncologists generally refer patients to a cardiologist for close monitoring. Sometimes, the effect on the heart is immediate, but in some, the risk rises over time. This risk often can be lowered or even negated with appropriate treatment by a knowledgeable cardiologist.
However, newer cancer treatments, including biologics and targeted molecular therapies, appear to have dangers of their own that can include hypertension, heart failure, QT-segment prolongation (which can cause a fatal arrhythmia), blood clots, and pulmonary hypertension. Unfortunately, oncologists do not know how to predict who will be affected. In any case, most cardiologists have little experience with these drugs and may not know the best way to prevent their dangerous side effects.
Lowering Risk. Professional cardiology associations in North America and Europe are in the process of developing guidelines for treating patients and training physicians in this new subspecialty. But the European Society of Cardiology’s cardio-oncology position paper will address how to evaluate patients before and after cancer treatment, how to prevent toxic effects on the heart and reduce risk factors, and how to treat patients when cardiac problems arise.
Dr. Jose Luis Zamorano, President-Elect of the European Association of Echocardiography and Director of the Cardiovascular Institute, University Clinic San Carlos, Madrid, said “Can you imagine what happens to the patient if during treatment someone recommends to the oncologist to reduce the dose of the drug, or even stop treatment? It cannot be the decision of a single person. It should be a clear protocol done by real experts in the field using a multidisciplinary approach.”
Filling in the Missing Links. As participants in an evolving specialty, cardio-oncologists will have to work with the information they have and create clinical studies to fill in knowledge gaps. For example, no one knows what happens to patients who stop taking a cardiotoxic drug before completing the recommended number of cancer treatments, or those who are never referred to a cardiologist for care.
But perhaps more relevant to today’s patients, guidelines being developed for use by these rising specialists will offer evidence-based direction for treating heart problems that arise from chemotherapy, and more importantly, helping to prevent them.
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