Young women treated with radiation therapy (RT) for left-sided breast cancer have an increased risk for coronary artery disease (CAD) compared with those treated for right-sided breast cancer, according to a study published in the Sept. 1 issue of JACC: CardioOncology.
Lauren E. Carlson, M.P.H., from the Memorial Sloan Kettering Cancer Center in New York City, and colleagues reported CAD risk among 1,583 women aged younger than 55 years when diagnosed with breast cancer between 1985 and 2008. The risk for radiation-associated CAD was assessed by comparing women treated with left- versus right-sided RT. Overall, 972 women were eligible for analyses and were followed for a median of 14 years.
The researchers found that the 27.5-year cumulative incidences of CAD were 10.5 and 5.8 percent for women receiving left- versus right-sided RT, respectively. In the multivariable Cox model, the corresponding hazard ratio for CAD was 2.5 for left- versus right-sided RT. No statistically significant effect modification was seen by any factor evaluated.
“This study also reaffirms the role of prolonged surveillance for CAD in younger survivors,” write the authors of an accompanying editorial. “Given the latency between radiation exposure and the development of cardiovascular events, it is important that young women who have received left breast RT be considered at higher risk over their lifetime.”
Several authors disclosed financial ties to the pharmaceutical industry.