Radiation Therapy May Increase Risk Of Heart Problems: Study

The findings of a new study suggest that radiation therapy may increase the risk of heart problems among individuals with pre-existing heart disease. 

Researchers at the University of Michigan warn that doctors should be concerned about the risk of cardiac injury when conducting radiation therapy on some cancer patients; particularly those with non-small-cell lung cancer (NSCLC). The findings were published in the Journal of Clinical Oncology‘s May edition.

The researchers looked at data on 125 patients with stage II to stage III NSCLC, who were treated with radiation therapy at two centers from 2004 to 2013. They looked at cardiac events suffered by those patients.

According to the findings, 19 patients had what is considered a grade 3 cardiac event, or something more serious, at a median of 11 months after radiation therapy. The data indicates that those patients with heart disease who underwent radiation therapy had nearly triple the risk of suffering a cardiac event, and those heart events may have been associated with decreased chances of overall survival.

The study also found a slight increase in risk among those who received a higher mean heart dose of radiation.

“Pre-existing cardiac disease and higher mean heart dose were significantly associated with higher cardiac event rates,” the researchers concluded. “Caution should be used with cardiac dose to minimize risk of radiation-associated injury. However, cardiac risks should be balanced against tumor control, given the unfavorable prognosis associated with disease progression.”

The findings are similar to those from a 2013 study published in the New England Journal of Medicine, which found that radiation therapy for breast cancer can increase a woman’s risk of suffering a heart attack or other heart problems.

According to that study’s findings, the rate of major coronary events increase linearly by 7.4% for every Gray of radiation the heart received.

A Gray is a unit of measurement used to determine how much ionizing radiation an object has absorbed. One gray equals the absorption of one joule of energy per kilogram of matter.