Survivors of childhood cancer may have increased risk of cardiovascular disease as adults

Adults who received cancer-related cardiotoxic therapy as children are at an increased risk for cardiovascular disease later in life, according to a cross-sectional study.

The researchers mentioned that survivors of childhood cancer may have cardiovascular disease at an earlier age and may have substantial morbidity.

Lead researcher Daniel A. Mulrooney, MD, MS, of St. Jude Children’s Research Hospital in Memphis, Tenn., and colleagues published their findings online in the Annals of Internal Medicine on Jan. 4.

“We identified considerable cardiovascular disease in this large cohort of adult survivors of childhood cancer,” they wrote. “The prevalence is inconsistent with the chronological age of the population and suggests a substantial future health care burden. Clinically, these data may guide stratification of risk factors, screening practices, health counseling, and potential therapeutic measures aimed at changing the disease trajectory in this young adult population.”

The researchers noted that advances in medicine have led to 5-year survival rates in pediatric oncology of more than 80 percent. By 2020, there will be an estimated 500,000 adult survivors of childhood or adolescent cancer. However, the researchers cited data that showed 5-year survivors of childhood cancer have an 8-fold increased risk of death compared with the general population and that premature cardiovascular disease is a leading cause of death.

In this analysis, the researchers evaluated participants from an ongoing cohort study of adults who were diagnosed with cancer as children, treated with cardiotoxic therapy at St. St. Jude Children’s Research Hospital and survived at least 10 years after the diagnosis. They defined cardiotoxic therapy as anthracycline chemotherapy or cardiac-directed radiation therapy.

The 1,853 participants were recruited from 44 states and 28 countries. They completed a comprehensive initial comprehensive risk-based health evaluation as of April 30, 2013 as well as a detailed health questionnaire. They also underwent a medical evaluation that included a history and physical examination, fasting laboratory testing, echocardiography and electrocardiography.

Of the participants, 52.3 percent were men. The median age at diagnosis was 8 years, while the median age at the time of study was 31. The median time from diagnosis to study was 22.6 years. Of the survivors of childhood cancer, 67.2 percent received treatment for leukemia or lymphoma, 14.0 percent received treatment for sarcoma, 7.2 percent received treatment for Wilms tumor, 4.5 percent received treatment for neuroblastoma, 4.3 percent received treatment for central nervous system tumors and 2.8 percent received treatment for other tumors.

The researchers found that 7.4 percent of survivors had cardiomyopathy, 3.8 percent had coronary artery disease, 28.0 percent had valvular regurgitation or stenosis and 4.4 percent had conduction or rhythm abnormalities.

They added that the prevalence of each cardiac condition increased with age and that nearly all of the survivors were asymptomatic. In addition, the odds of cardiomyopathy were significantly associated with male sex, anthracycline doses of 250 mg/m2 or greater, cardiac radiation exposure greater than 1500 cGy and hypertension.

Only 61 percent of the survivors participated in this study, which the researchers said could have led to a selection bias. They also mentioned they did not routinely obtain medical records for participants who did not report a cardiac event. Further, the study did not include a control group and only enrolled participants who received cardiotoxic therapies, which may have limited the ability to generalize the findings.