ECHO FOLLOW UP FOR PATIENTS TREATED WITH CHEST RADIOTHERAPY

LIEGE, Belgium — Patients treated with radiotherapy to the chest for Hodgkin's disease, or breast, lung, or esophageal cancer, should have an echocardiogram every five to 10 years to detect radiation-induced heart disease (RIHD), according to a new consensus statement [1].

Experts from the European Association of Cardiovascular Imaging (EACVI) of the European Society of Cardiology and the American Society of Echocardiography have developed the first consensus statement to address screening for RIHD in patients who have received radiotherapy to the chest.

The statement was copublished this month in the European Heart Journal--Cardiovascular Imaging and Journal of the American Society of Echocardiography.

Risk of RIDH

Compelling evidence shows that radiotherapy to the chest can increase the risk of RIHD, including pericarditis, valvular heart disease, myocardial damage, microvascular dysfunction, CAD, myocardial ischemia, and restrictive cardiomyopathy, the group writes.

RIDH is estimated to occur in 10% to 30% of patients who receive radiotherapy to the chest. The risk depends on the radiation dose and length of exposure. Strategies to prevent RIHD include altering the radiation field and shielding the heart during radiation.

Studies have reported that the relative risk of RIHD is more than 6.3-times higher in patients treated with radiation for Hodgkin's disease, and 2- to 5.9-times higher in patients treated with radiation for breast cancer.

Risk factors for RIHD include:

• Anterior or left chest irradiation
• Age <50 p="" years="">
• CVD risk factors (diabetes mellitus, smoking, overweight, moderate or severe hypertension, hypercholesterolemia)
• Pre-existing CVD
• High cumulative dose of radiation (>30 Gy)
• High dose of radiation fractions (>2 Gy/day)
• Tumor in or next to the heart
• No shielding of the irradiated area
• Concomitant chemotherapy (especially with an anthracycline)

High-risk patients, defined as those who received anterior or left-side chest irradiation and have one or more other risk factors for RIHD, are most likely to benefit from screening.

Patients treated in the 1980s with high-dose radiation techniques are at higher risk of LV dysfunction, valvular abnormality, and CAD, the group writes.

RIHD manifests slowly, five to 20 years after radiation treatment, "making a strong argument for screening because the prevalence and severity of [CV] abnormalities are often clinically unrecognized," the authors note.

"Raising the Alarm" to Look for CVD

Based on expert opinion and available data, the consensus statement recommends:

• Before starting radiotherapy to the chest, patients should have a baseline echocardiogram to evaluate cardiac morphology and function, and identify any abnormalities.
• After radiotherapy, patients should have a yearly physical exam during which their physician pays "close attention to symptoms and signs of heart disease that might otherwise be overlooked in this generally young population."
• Modifiable CVD risk factors should be corrected.
• Patients who have a cardiac abnormality or are asymptomatic but at high risk of CVD should have an initial transthoracic echocardiogram screening test five years after radiation treatment.
• Asymptomatic patients who are not at high risk of CVD should have an initial screening echocardiogram 10 years after radiation treatment.
• After an initial screening electrocardiogram, patients should have an echocardiogram every five years.
• When the findings from an echocardiogram are equivocal, cardiac computed tomography (CT), cardiac magnetic resonance (CMR), and nuclear cardiology can be used to confirm and evaluate the extent of RIHD. For example, CMR can be used to precisely assess the presence of myocardial fibrosis, and CT can be used to more accurately assess cardiac calcification.

"We wrote the expert consensus to raise the alarm that the risks of radiation-induced heart disease should not be ignored," task force chair and EACVI president Professor Patrizio Lancellotti(University of Liege Hospital, Belgium) said in a statement.

Investigators need to set up a registry of patients with RIHD "to determine the true prevalence of the disease and collect outcome data," he added. "This, together with screening, should reduce the risk of patients developing RIHD and enable us to treat it early when it does occur."

The authors declared no conflicts of interest.