Abstract 11591: Impact of Curative Thoracic Radiation Therapy for Cancer in Patients With Coronary Artery Stents
Background: Thoracic external beam radiation therapy (RT) for cancer is associated with long term cardiotoxic side effects. While intravascular brachytherapy has been previously used to treat coronary in-stent restenosis, it is unknown whether external beam RT is harmful or even protective with regards to stent related outcomes. The aim of this study was to determine whether RT affects rates of symptomatic stent failure.
Methods: We retrospectively analyzed baseline demographic, oncologic, and cardiovascular characteristics in subjects who had previously been treated with a coronary stent and subsequently had curative thoracic RT (>30 Gray, except for lymphoma) for cancer at Mayo Clinic between May 1998 to October 2012. Outcomes were compared to a propensity-matched control cohort of patients with coronary stents not treated with RT, taking into account the time delay from stent to RT for the outcome analysis in controls. Primary endpoint was target lesion revascularization (TLR). Secondary endpoints were myocardial infarction (MI) and cardiac death.
Results: We identified 115 patients who were treated with thoracic RT (median interval 3.6 years) after coronary artery stenting. They were matched with 1,930 controls who had coronary stenting but never had RT. After a median follow-up of 2.1 years, patients treated with RT had similar rates of TLR (RT 3.2%, controls 6.6%; p=0.31; Fig. A), MI (4.8% vs 4.3%; p=0.93; Fig. B) and cardiac death (2.3% vs 3.6%; p=0.66; Fig. C) when compared with controls. As expected, overall survival was worse (48.6% vs 13.9%; p<0.001; Fig. D) in the RT cohort.
Discussion: Thoracic external beam RT for cancer, at curative doses, does not affect the rates of coronary stent failure. Thus, a prior history of coronary artery stenting should not by itself modify the decision to use curative thoracic RT, and optimal treatment of the malignancy should be the goal.
- © 2013 by American Heart Association, Inc.