Study Suggests Less Frequent Cardiac Screening May Be Preferable for Survivors of Childhood Cancer
One of the first studies to analyze the effectiveness of screening survivors of childhood cancer for early signs of impending congestive heart failure found improved health outcomes but suggested that less frequent screening than currently recommended may yield similar clinical benefit. Researchers used a simulation-based model to estimate the long-term benefits associated with routine screening. The findings by Yeh et al, published in the Annals of Internal Medicine, suggest that the current congestive heart failure screening guidelines for survivors of pediatric cancer should be reexamined.
Current Screening Guidelines
The current guidelines recommend that survivors treated with chemotherapy agents known to affect long-term heart health be screened as often as every year, with a schedule dependent on their level of congestive heart failure risk. The new study suggests that screening survivors less often may be nearly as effective in detecting heart disease early. Some survivors might be better served by a different method of screening than the one currently used.
“It is important to monitor survivors so we can reduce the late effects of treatment whenever possible, but we may be asking them to be tested too often, which burdens both individuals and the health-care system,” said senior author Lisa Diller, MD, Chief Medical Officer of Dana-Farber/Boston Children’s Cancer and Blood Disorders Center. “We think it is worthwhile to review the current congestive heart failure screening guidelines.”
“Our findings suggest that there is a long-term benefit in screening survivors at elevated risk for congestive heart failure,” said lead author Jennifer Yeh, PhD, of the Center for Health Decision Science at Harvard School of Public Health. “Yet less frequent screening than currently recommended may be reasonable when other factors are considered. We hope these results can help inform the ongoing discussion about screening childhood cancer survivors.”
Childhood Cancer Survivors at Higher Risk for Heart Disease
As cure rates of pediatric cancers have risen, increasing numbers of survivors are at a substantially higher risk of heart disease, including congestive heart failure, compared to the general population. The increase in risk varies depending on several factors, including whether a patient was treated with anthracyclines and/or radiation to the heart. For instance, those who received no or low (< 250 mg/m2) cumulative doses of anthracyclines have a relatively low lifetime risk of developing congestive heart failure, while those who received large (≥ 250 mg/m2) cumulative doses are at higher risk.
The Children’s Oncology Group (COG) currently recommends that survivors undergo screening by echocardiography for asymptomatic left-ventricular dysfunction. If left untreated, this clinically silent condition can progress to congestive heart failure, so clinicians typically prescribe beta blockers and ACE inhibitors to patients with signs of asymptomatic left-ventricular dysfunction. COG recommends that patients at high risk of developing congestive heart failure be screened every 1 to 2 years and those at low risk be screened every 2 or 5 years.
“Survivors are screened for decades and face risks for other late effects, as well,” Dr. Diller said. “We need to consider carefully how often we ask survivors to be screened over the course of their lives, given the substantial cumulative economic impact and anxiety that screening may cause.”
Study Details
To estimate the clinical benefits and cost-effectiveness of the current heart screening guidelines, Drs. Diller, Yeh and their coauthor, cardiologist Anju Nohria, MD, of Brigham and Women’s Hospital, constructed a computer model of a virtual cohort of 15-year-olds who had survived cancer at least 5 years. Using data from the Childhood Cancer Survivors Study and the Framingham Heart Study, the researchers modeled the cohort’s congestive heart failure risk and clinical progression over the course of survivors’ lifetimes. Their analysis suggests that routine screening may prevent as many as one in 12 cases of congestive heart failure.
The authors then used Medicare data to estimate the costs and value (expressed in cost per quality-adjusted life year) of different screening schedules (ie, every 1, 2, 5, or 10 years) and methods (echocardiography vs cardiac magnetic resonance imaging [MRI]) for the different congestive heart failure risk groups (ie, low, high).
Results
At a cost-effectiveness threshold of $100,000/quality-adjusted life year, the model’s results indicate that echocardiographic screening might not be the best value for resources invested to reduce lifetime congestive heart failure risk among survivors at low risk of developing the disease. On the other hand, the data suggest that biennial echocardiography screening may be a high-value strategy for high-risk survivors.
The simulation’s data also suggested that cardiac MRI may be preferable to echocardiography as a screening method, with cardiac MRI’s greater cost per test balanced by its greater sensitivity. According to the model, cardiac MRI-based screening of low-risk survivors every 10 years and high-risk survivors every 5 years was more cost-effective than any echocardiography-based schedule.
Lastly, the data suggest that it may be most beneficial to treat high-risk survivors before signs of asymptomatic left-ventricular dysfunction even appear. For instance, proactively treating all high-risk patients in the virtual cohort with ACE inhibitors and beta blockers reduced their lifetime congestive heart failure risk more than if they received an echocardiograph every 2 years, although additional clinical studies on the benefit of the treatments are needed to support this strategy in practice.
The researchers relied on simulation modeling using the best available clinical and epidemiologic data because of the immense logistical obstacles to conducting prospective randomized clinical studies of survivors’ long-term cardiovascular outcomes. The number of survivors that clinical studies would need to enroll and follow for years is challenging given how rare childhood cancers are. Yet guidance on the health benefits associated with current recommendations is needed.
“Our findings suggest that current recommendations for cardiac assessment may reduce systolic congestive heart failure incidence, but less frequent screening than currently recommended may be preferred,” the study concluded. “Possible revision of current recommendations is warranted.”
Dr. Yeh is the corresponding author of the Annals of Internal Medicine article.
The study was supported by the National Cancer Institute.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
