ABSTRACT
The lungs fill the largest share of the thoracic cavity and are the primary site of several carcinomas and a frequent site of metastasis for multiple other tumors. Trachea and bronchi connect the pharynx to the lungs and are essential anatomical structures to ensure transport of air into the alveoli and enable exchange of gases. Acute radiation-induced lung disease, manifesting as pneumonitis, develops approximately 6–12 weeks after irradiation. As for the lung, numerous models have been proposed to predict esophageal toxicity after irradiation. Organs such as the esophagus, the trachea and large bronchi, and large blood vessels are especially vulnerable because functional failure can lead to serious, potentially life-threatening complications. In many cases of sever esophageal toxicity, the initial or recurrent cancer involved the esophagus and the severe natural course of the disease therefore contribute to the development of the toxic event.
