Abstract
Background: The Children's Oncology Group Long-Term Follow-up Guidelines recommend surveillance for late effects in pediatric cancer survivors based on therapeutic exposures. In particular, the Guidelines recommend an echocardiogram, or comparable imaging, every 2 to 5 years to evaluate cardiac function in survivors exposed to anthracycline chemotherapy. However, little is known about the real-world utilization of cardiac surveillance tests following the completion of cancer therapy.
Objective: This study fills this gap by describing the proportion of anthracycline-treated survivors of pediatric cancer who received surveillance for cardiac function following the completion of their cancer therapy.
Method: We developed an algorithm to identify a cohort of pediatric cancer survivors using the IBM MarketScan ® Commercial Claims and Encounters Database (a nationwide private insurance enrollment and claims database). The cohort for inclusion was enrollees who (1) received anthracycline for blood cancer (leukemia or lymphoma); (2) aged ≤21 years at cancer diagnosis; (3) completed all cancer therapy between 2009 and 2018; and (4) remained continuously insured for at least one year post-therapy. Outcomes assessed included the receipt of: (1) echocardiogram, (2) cardiac magnetic resonance imaging (MRI), (3) multiple gate acquisition (MUGA) scan, and (4) any of the aforementioned cardiac surveillance tests over the 5-year period after the completion of all cancer therapy. The Kaplan-Meier (K-M) method was used to estimate the cumulative incidence of an event post-therapy, where the event was defined as the initial healthcare claim for a cardiac surveillance test. Individuals were censored if they had not received a test by study termination or were lost to follow-up at any time during the 5 years post-therapy. Multivariate Cox proportional hazard models were estimated to identify the demographic and cancer-related factors strongly associated with the initial test receipt.
Results: Among 1,914 eligible blood cancer survivors, 259 (13.5%) survivors received a hematopoietic stem cell transplantation (HSCT; Table 1). The K-M estimated probability of receiving a cardiac surveillance test by 5 years post-therapy was 61.0% (95% Confidence Interval [CI]: 57.2% to 64.7%), with the median time to the initial test being 2.6 years (95% CI: 2.2 to 3.1 years) from therapy completion. The vast majority of cardiac surveillance test users underwent an echocardiogram (n=850; versus only 10 who had a cardiac MRI, and 14 who had a MUGA scan) by the end of their follow-up period.
The proportion of survivors who had an initial cardiac test increased over time but varied by age at cancer therapy completion and the receipt of HSCT. The K-M estimated probability of receiving an initial test by 5 years post-therapy was: 86.0% (95% CI: 77.3% to 91.6%) for children (ages ≤11 years), 85.0% (95% CI: 75.4% to 91.1%) for adolescents (ages 12-17 years), and 36.8% (95% CI: 32.6% to 41.0%) for young adults (ages 18-28 years; Figure 1). Multivariate Cox models showed that compared with children, adolescents were more likely to receive an initial cardiac test (Hazard Ratio [HR] = 1.3; 95% CI: 1.1 to 1.5), while young adults were less likely to receive a test (HR = 0.4; 95% CI: 0.3 to 0.5). In addition, survivors who received a HSCT were more likely than those who did not to complete an initial cardiac test (HR=1.8; 95% CI: 1.5 to 2.2).
Conclusions: This nationwide, claims data-based study showed that a substantial proportion of anthracycline-exposed survivors of blood cancers had not completed a cardiac surveillance test within 5 years post-therapy. Within this high-risk population, young adults were significantly less likely to receive surveillance testing for the prevention and early detection of cardiac dysfunction.
No relevant conflicts of interest to declare.
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