Since the 1970s, serious heart disease among childhood cancer survivors had declined remarkably, a new study finds.
The decline suggests that efforts to make cancer treatments, including radiation, less toxic are paying off, researchers say.
For the study, researchers led by Dr. Daniel Mulrooney, from St. Jude Children's Research Hospital in Memphis, Tenn., collected data on more than 23,000 U.S. adults included in the Childhood Cancer Survivor Study who had survived the most common childhood cancers.
Specifically, the team members looked at heart failure, coronary artery disease, heart valve defects, damage to the heart tissue lining and heart rhythm problems.
They also took into account risks for heart disease, such as diabetes, high blood pressure and cholesterol levels, smoking, exercise and weight.
From the 1970s to the 1990s, doses of chemotherapy drugs decreased, as did the doses of radiation.
Exposure to cardiac radiation dropped from 77% of survivors treated in the 1970s to 40% treated in the 1990s, the researchers noted.
They found that the risk for coronary artery disease dropped from 0.38% in the 1970s to 0.24% in the 1980s and 0.19% in the 1990s. The decreases were mostly due to a decline in heart disease among survivors of Hodgkin lymphoma, a form of cancer of the white blood cells.
The drop in the risk for heart failure among patients treated in the 1990s, however, was not statistically significant, Mulrooney's team said.
This study can't prove that changes in treatment are the cause of the decline in heart disease, only that the two are associated.
The report was published Jan. 15 in the journal BMJ Today.
"These results suggest that efforts to modify cancer therapies in children and promote health surveillance for survivors are beginning to show benefits not only in overall survival but also in late adverse cardiac effects," the researchers said in a journal news release.
For more on childhood cancers, see the U.S. National Cancer Institute.