Monitoring Radiobiological Effects in Thoracic Malignancy by Using Myocardial Perfusion Scan

Background: Chemoradiation is an important treatment strategy of locally advanced inoperable or unresectable disease. Radiation dose is an independent predictor of a pathological response. In addition, chemotherapy has further impact on the aspect of outcome. Improvements in local treatment delivery are needed to facilitate dose escalation and to minimize toxicity. There have been sequential improvements in tumor localization, radiation planning and delivery over the years. Helical tomotherapy nowadays provides the most precise data on radiotherapy (RT) dose delivered to thoracic malignancies, and allows greater sparing of the heart from doses associated with increased complications. However, heart disease shows a wide spectrum of pathologies, and multiple risk factors related. The damage of the myocytes may lead to not only myocardial perfusion defects, but also in functional deterioration, or even in biomarkers. Since the impact of radiation-induced heart injury in patients with thoracic malignancies (including esophageal cancer, lung cancer, et al) is poorly documented, we try to delineate of RT-related cardiac effects and clinical impacts. Objective: This study aims to investigate the correlation of post-tomotherapy cardiovascular effects with myocardial perfusion and cardiac functional studies. Methods: The study plans to enroll thoracic cancer patients who will undergo local RT after complete staging. Patients will receive global risk scoring assessment (Framingham Risk Score, FRS), blood sampling for basic biochemistry, inflammatory biomarker, and myocardial perfusion image (MPI) at the time points of before and after RT. The results of MPI will be analyzed in qualitative visual interpretation of perfusion patterns, and functional quantitative data for cardiac functional parameters as well. The patients will be regular followed-up in CV OPD, following clinical judgement and guideline. The association between baseline and follow-up MPI, biomarker and cli