The medications that help thousands of children fight off cancer also have a dangerous side: They can cause life-threatening heart damage. But City of Hope researchers have found a possible way to identify children most at risk for these effects before kids ever start treatment.

Smita Bhatia found why some children are at high risk of a treatment-related heart disease. (Photo by Darrin S. Joy)

The findings bring scientists a step closer to genetic tests that might reduce cancer patients’ risk of treatment-related heart damage called cardiomyopathy. This life-threatening weakening of the heart muscle can result from taking drugs called anthracyclines.

Anthracyclines are a type of antibiotic that comes from certain bacteria. They’ve been in use against cancer since the 1960s. 

“Anthracyclines are very powerful drugs that help us fight leukemia, lymphoma and other cancers in children, as well as diseases like breast cancers in adults,” says Smita Bhatia, M.D., M.P.H., Ruth Ziegler Chair in Population Sciences. About half of today’s frontline cancer regimens include these drugs.

The study — the largest of its kind ever reported — involved nearly 500 teens and young adults nationwide who were treated for pediatric cancer, including 170 who later developed heart problems. Researchers found that patients who had a particular, common genetic factor faced a high risk of developing cardiomyopathy even after using low doses of anthracyclines.

Now that they know this genetic factor spotlights patients who are likely to develop heart problems, the scientists hope to help develop genetic tests that physicians could use to check for risk. Physicians could adjust their treatments in these children to protect their hearts.

The researchers also plan to follow more patients and are conducting studies to look for other genes that play a part.

Cardiomyopathy is one of many late effects of childhood cancer treatment, and Bhatia and her colleagues are attacking these late effects from many angles.

“The science is really coming together in this area,” Bhatia says, “and it’s exciting for us to be finding answers to a significant problem.”