May 16, 2008 -- Kids who beat childhood cancer are five to 10 times more likely than their healthy siblings to develop heart disease in early adulthood, according to the largest study ever to look at the issue.
"Childhood cancer survivors in their 20s are developing the kinds of heart problems we typically see in older adults," says lead researcher Daniel A. Mulrooney, MD, assistant professor of pediatrics at the University of Minnesota's Masonic Cancer Center in Minneapolis.
There are more than 270,000 survivors of childhood cancer in the United States, Mulrooney says. He is scheduled to present the findings at the annual meeting of the American Society of Clinical Oncology (ASCO).
More than 65% of children and young adults are now cured of cancer, according to the American Cancer Society.
Heart Risks Increased in Child Cancer Survivors
The analysis from the Childhood Cancer Survivor Study involved more than 14,000 young adults who were diagnosed with a childhood cancer between 1970 and 1986. They had survived a variety of cancers, including Hodgkin's disease, brain or kidney tumors, leukemia, or lymphoma.
Participants, whose average age was 28 at the time of the analysis, were diagnosed with cancer at an average age of 8. They were followed for an average of 20 years.
Compared with their healthy siblings, the cancer survivors were:
10 times more likely to have plaque buildup in their arteries, or atherosclerosis
Six times more likely to have congestive heart failure
Five times more likely to have had a heart attack
Previous findings from the study, which features the largest group of people in the world who beat childhood cancer, showed that survivors are also at increased risk of other health woes, including lung scarring, blood clots, infertility, and second cancers.
Mulrooney tells WebMD that a major culprit behind the increased risk of heart disease as well as other health woes is the radiation used to diagnose and treat some cancers. Chemotherapy drugs called anthracyclines, such as Adriamycin, are also to blame, he says.
Mulrooney says that recent changes in the delivery of radiation and chemotherapy probably place children today at lower risk of secondary health problems.
For example, radiation is more targeted, right to the area of a tumor, "which would hopefully spare the heart," he says.
At the same time, some of the same chemotherapy drugs used in the 1970s are still helping people beat cancer today. And there are no long-term data to prove today's regimens are safer, Mulrooney notes.
Regular Checkup Stressed
The important thing for survivors to know is that the impact of these health problems can be reduced with regular checkups, says Richard L. Schilsky, MD, president-elect of ASCO and professor of medicine at the University of Chicago.
"As childhood cancer survivors age, they often transfer their care to a primary care physician and see their oncologist less frequently, if at all, as is appropriate.
"But it becomes incumbent upon the patients and the primary care physicians to be aware of the cancer history and its potential consequences," Schilsky tells WebMD.
Mulrooney agrees. "The average age at which our young survivors developed heart problems, 28 years, is much younger than when most primary care physicians start screening for cardiac disease."