The prevalence of myocardial ischemia after concurrent chemoradiation therapy as detected by gated myocardial perfusion imaging in patients with esophageal cancer

The detection of myocardial perfusion abnormalities after radiation therapy (RT) has been investigated previously in patients with lymphoma and breast cancer. However, the prevalence and association of such abnormalities with RT in esophageal cancer patients have not been investigated previously. Methods: The prevalence of myocardial perfusion abnormalities detected using gated myocardial perfusion imaging (GMPI) in patients with esophageal cancer after RT (RT group) was compared with that in patients with esophageal cancer who did not undergo RT (NRT group). The patients' data were extracted from a prospectively collected database. The results of GMPI that were read by multiple readers were tested further by an expert reader who was unaware of the patients' clinical information. This reader's findings were correlated with the different RT isodose lines as seen in the CT for RT planning. Isodose lines containing the affected segments in GMPI as well as the rest of the left ventricle were recorded. Additionally, information with regard to the mean radiation dose to the heart for each patient was collected. An overall, mean radiation dose to the heart in patients with abnormal GMPI studies was compared with that in patients with normal GMPI studies. Results: Fifty-one patients were included, 26 in the RT group and 25 in the NRT group. The mean and median interval between FIT and GMPI was 7.5 and 3.0 mo, respectively. We identified myocardial perfusion defects in 14 patients (54%) in the RT group and in 4 patients (16%) in the NRT group. Eleven patients (42%) in the RT group had mild inferior wall ischemia versus only 1 patient (4%) in the NRT group (P = 0.001). All of the patients with inferior wall ischemia had distal esophageal cancer. The remaining 12 patients in the RT group and 21 patients in the NRT group had normal GMPI results. The mean left ventricular ejection fraction was 59.0% +/- 10.7% in the RT group and 59.3% +/- 9.8% in the NRT group (P = not significant). Good agreement was found between the GMPI results interpreted by multiple readers and those of the single expert reader (K = 0.84). In 7 of 10 patients (70%) who had abnormal GMPI results in the RT group, the myocardial perfusion defect was encompassed in RT isodose lines >= 45 Gy, whereas in only 5 of 20 patients (25%) the normal left ventricle was included in the FIT isodose line >= 45 Gy. Conclusion: FIT is associated with a high prevalence of inferior left ventricular ischemia, as detected using GMPI in patients with distal esophageal cancer. Most perfusion defects are encompassed within an isodose line >= 45 Gy in the RT plan.