Cardio-Oncology: Heart-Smart Cancer Careby Judi Ebbert, PhD, MPH, RN Health Writer
Heart disease and cancer are the top two causes of death in the United States. About 630,000 Americans die from heart disease each year, and nearly 596,000 die from cancer. Annual deaths from either disease alone are about equal to the population of Las Vegas. Risk for both diseases increases with age, and a large proportion of people in the U.S. are over age 65. Many older people have both diseases, and that requires a special kind of expert to care for them.
How can cancer treatment harm the heart?
Some cancer therapies can damage the heart. Because the cardio-toxic effects of certain treatments are often delayed, doctors only discovered these heart risks after advances in cancer care increased patients’ long-term survival. With this discovery came innovation: the subspecialty of cardio-oncology to prevent damage from cardio-toxic cancer treatment. Cardio-oncologists work with a patient’s entire care team to prevent and minimize heart damage from radiation therapy and certain cancer drugs.
What kind of damage can occur?
Although it’s a vital organ and a strong muscle, the heart has limits. Heart cells rarely reproduce, and the heart doesn’t heal easily. Certain parts of the heart are at greater risk for harm from cardio-toxic therapy, including the:
- Myocardium (muscular middle layer)
- Pericardium (outer, two-walled sac)
- Valves (“gates” that let blood flow in one direction through the heart)
- Coronary arteries (supply blood and oxygen to the heart)
- Large vessels (they carry blood to and from the heart)
How can certain cancer treatments damage the heart?
Certain therapies can lead to ischemia, which occurs when not enough blood reaches a part of the heart, causing cell death. Some therapies can lead to arrhythmia (abnormal heart rate) and high blood pressure, which can stress the heart. Left ventricular dysfunction (LVD) can also occur, causing the chief blood-pumping chamber to work too hard. Heart failure happens when the heart can’t pump enough blood for the body’s needs, triggering shortness of breath, fatigue, and leg swelling.
How can radiation therapy harm the heart?
The purpose of radiation therapy is to kill cancer cells. The international radiation dosage unit is the Gray, abbreviated to Gy. Radiation to the chest at more than 30 Gy may do damage to the heart that may not become apparent for 10 years. Radiation damage usually affects the large and small blood vessels and the valves. Your risk for damage goes up if you're at a younger age when you receive radiation, and if you have other cardiovascular risk factors.
What can be done to prevent radiation therapy from damaging the heart?
Lower doses and shorter duration of radiation can decrease heart risk. Awareness of preexisting cardiovascular risk factors can be factored into cancer treatment plans. Having a cardio-oncologist on the care team can ensure that steps are taken to minimize risk, which include ongoing surveillance to observe the impact of therapy on the cancer as well as the heart.
Which cancer drugs can damage the heart?
Cardio-oncologists can prevent and minimize potential heart damage from the following cancer drugs known to pose heart risks: anthracyclines such as doxorubicin and daunorubicin, HER2 inhibitors such as trastuzumab, mitotic inhibitors such as docetaxel or paclitaxel, alkylating agents such as cyclophosphamide or ifosfamide, proteasome inhibitors such as bortezomib or carfilzomib, small tyrosine kinase inhibitors such as sunitinib or imatinib, and immune modulators such as ipilimumab or nivolumab.
What can a cardio-oncologist do to protect the heart?
In addition to knowing your heart health history, the cardio-oncologist will monitor your heart during treatment. If there are symptoms of left ventricular dysfunction, chemotherapy can be adjusted or discontinued, and corrective drugs can be prescribed. At the end of cancer treatment, surveillance will continue and be tailored to each patient’s risk for heart problems.
How is cardio-oncology changing outcomes?
Cardio-oncologists can detect the impact of cancer treatment on the heart early, before damage is done. They monitor and intervene by collaborating with the oncologist. They may recommend reductions of chemo dosing and frequency and may prescribe medications to prevent heart damage. Cardio-oncologists gauge risk and respond proactively to support a successful, uninterrupted course of cancer therapy that preserves heart health. This makes them key contributors to longevity and quality of life.
How do you find a cardio-oncologist?
There are several ways to find a cardio-oncologist. Ask your primary care doctor, oncologist, or cardiologist for recommendations. Do a computer search or call treatment centers and ask if they have a cardio-oncology program (COP). COPs are found in large academic medical centers and cancer facilities. Cardio-oncologists work with oncologists and cardiologists to ensure win-win care that controls cancer and preserves heart health.