Screening young-adult survivors of childhood cancer revealed “considerable” subclinical cardiovascular disease, including valvular regurgitation or stenosis in 28%, cardiomyopathy in 7.4%, conduction or rhythm abnormalities in 4.4%, and coronary artery disease in 3.8%, according to a report published online Jan. 4 in Annals of Internal Medicine.
Most of the 1,853 study participants (median age, 31 years) were asymptomatic, with only 4 reporting occasional chest pain and only 1 reporting occasional palpitations. Yet, on careful examination, many showed significantly impaired physical performance. For example, “asymptomatic” young-adult survivors found to have cardiomyopathy and CAD were twice as likely as others to perform poorly on the 6-minute walk test, said Dr. Daniel A. Mulrooney of St. Jude Children’s Research Hospital, Memphis, and his associates.
The number of adult survivors of childhood cancer is predicted to exceed 500,000 by 2020, and the late effects of cancer treatment, primarily on the heart, are the chief cause of death among those who survive to 30 years. Few studies, however, have directly examined cardiac outcomes among survivors “because of the rarity of childhood cancer and the challenges of following patients across the life spectrum,” the investigators noted.
They were able to do so using data from the St. Jude Lifetime Cohort Study, focusing on patients aged 18 years and older from 44 states and 28 countries who had been treated with cardiotoxic therapy (anthracycline or chest irradiation) at St. Jude and survived 10 years or more after diagnosis. The participants’ median age was 8 years (range, 0-24) at diagnosis and 31 years (range, 18-60) at the time of the study. The median time since diagnosis was 23 years.
The study participants had been treated for leukemia or lymphoma (67%), sarcoma (14%), Wilms tumor (7%), neuroblastoma (5%), CNS tumors (4%), or other cancers (3%). They underwent a full medical evaluation plus echocardiography and electrocardiography.
Of particular concern was the finding that so many study participants had asymptomatic cardiomyopathy and were at high risk for heart failure. “At a median age of 31 years, we identified 7.4% of survivors with evidence of decreased systolic function, an estimate expected in a much older population,” they wrote. By comparison, in one study the rate of cardiomyopathy among healthy adults was less than 3% at ages 45-54 years, and it didn’t rise to 7% until ages 65-74 years, Dr. Mulrooney and his associates said (Ann Intern Med. 2016 Jan 4. doi: 10.7326/M15-0424).
The high (28%) frequency of valvular abnormalities – mitral or aortal regurgitation, stenosis, thickening, and calcification – also was of particular concern.
The prevalence of CV abnormalities increased with increasing patient age and with increasing doses of anthracycline and/or radiation exposure. Yet nearly 5% of the youngest patients – those aged 30 years or younger – showed evidence of cardiomyopathy.
Overall, the study findings suggest that CV disease represents “a substantial future health care burden” in this patient population. “Clinically, these data may guide stratification of risk factors, screening practices, health counseling, and potential therapeutic measures aimed at changing the disease trajectory in” these patients, the investigators said.
This study was funded by the National Cancer Institute and the American Lebanese Syrian Associated Charities. Dr. Mulrooney and his associates reported having no relevant conflicts of interest; their financial disclosures are available at acponline.org.