Radiation therapy (RT) for locally advanced non-small cell lung cancer (NSCLC) was linked to higher risk for cardiac events, particularly in patients with a history of cardiac disease or who received higher RT doses. The results of this study were published in the Journal of Clinical Oncology.1

Higher radiation doses has been associated with better tumor control in NSCLC which is often diagnosed at advanced stages and is associated with higher rates of locoregional relapse. Furthermore, cardiac toxicity is associated with higher doses of RT but research is limited on cardiac toxicities specifically in patients with locally advanced NSCLC.

Shruti Jolly, MD, associate professor of Radiation Oncology at the University of Michigan School of Medicine, and colleagues analyzed long-term data on the cardiac event rate of 4 prospective RT trials in patients with stage II or III NSCLC.

The study end points included development of a grade 3 or higher cardiac event after treatment, progression-free survival, and overall survival.

Data was analyzed on 125 patients with a median follow-up of 51 months. At baseline, 27% had a history of cardiac disease (n = 34) prior to treatment and 15% (n = 19) without cardiac disease had a Framingham risk score of 20% or more.

In total, 19 participants experienced a cardiac event grade 3 or higher with an incidence of 11% over 24 months (95% CI, 5%–16%). Grade 3 or higher cardiac events were signficiantly associated with pre-existing cardiac disease (HR 2.96, P =.04) and mean radiation heart dose (HR 1.07/Gy, P =.01) after multivariable analysis.

Decreased overall survival was associated with grade 3 or higher cardiac events (HR 1.76) and disease progression (HR 2.15) after multivariable analysis.

“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 researchers conclude.1

Reference

1. Dess RT, Sun Y, Matuszak MM, et al. Cardiac events after radiation therapy: combined analysis of prospective multicenter trials for locally advanced non-small-cell lung cancer. J Clin Oncol. 2017 Mar 16. doi: 10.1200/JCO.2016.71.6142 [Epub ahead of print]