Childhood cancer survivors are up to three times more likely than their cancer-free peers to develop various types of heart disease, according to an Aug. 26 study published in Circulation.
In an attempt to characterize the cardiac risks faced by young cancer survivors years down the line, first author Ashna Khanna, MSc, and colleagues at the University of Toronto analyzed data logged in POGONIS (Pediatric Oncology Group of Ontario Networked Information System), Ontario’s pediatric cancer registry. They studied 7,289 five-year cancer survivors and 36,205 matched controls, identifying cardiac events, diabetes and hypertension using hospital admission and physician billing codes.
In their paper, the authors said the majority of cardiology studies focused on childhood cancer survivors have revolved around anthracycline-related heart failure—an established risk in the population. But rather than limiting their study to HF, the team also considered risks and predictors of arrhythmias, pericardial disease, valvular disease and coronary artery disease in the same patient group.
Individuals in the study were an average of 7 years old when they were first diagnosed with cancer. After a median follow-up of 10 years, 203 survivors—2.8% of patients—experienced one or more cardiac events compared with 331—0.9%—of controls. Survivors saw 3.2 cardiac events per 1,000 person-years compared to 0.9 cardiac events per 1,000 person-years in the general population.
Khanna et al. also reported that among cancer survivors, childhood relapse or subsequent cancer, exposure to 250 mg/m2 or more of doxorubicin-equivalent anthracycline chemotherapy and diabetes were associated with higher risks of CVD. In particular, relapse, heavy exposure to doxorubicin-equivalent anthracycline chemo, diabetes and hypertension were linked to twofold, eightfold, fourfold and threefold increased risks of heart failure, respectively.
“Even at relatively young ages, survivors experienced a two- to tenfold increased risk of CVD relative to the general population,” the authors wrote. “Consistent with the literature, we found anthracycline dose predicted an increased risk of CVD overall and HF in particular. Although our univariate analyses demonstrated associations between chest-directed radiation and cardiac risk, this relationship was not significant in multivariable analyses.”
Khanna and colleagues said that since radiation-linked CVD can take a decade and a half or more to manifest—especially with modern radiation techniques—and their study was limited to an average 10 years of follow-up, the relationship between radiation exposure and CVD might become clearer as the cohort ages.
“Because the prevalence of CVD is expected to increase with age, this study reinforces the need for periodic CVD surveillance, and consideration of all CVD types, in childhood cancer survivors,” the authors wrote.
They also noted they were unable to assess behaviors like smoking, physical activity, diet and alcohol use during the study because their data was limited to administrative information.
After graduating from Indiana University-Bloomington with a bachelor’s in journalism, Anicka joined TriMed’s Chicago team in 2017 covering cardiology. Close to her heart is long-form journalism, Pilot G-2 pens, dark chocolate and her dog Harper Lee.