Radiation esophagitis is a potential complication of radiation therapy mainly seen in malignancies of the chest, most notably the lungs. Acute and chronic forms are described in the literature. In the acute setting, symptoms in the form of odynophagia and dysphagia appear a few weeks after initiating radiation therapy, whereas months or years may pass before the onset of complaints in chronic radiation esophagitis. The diagnosis is made through a comprehensive clinical assessment and imaging studies, endoscopy being the gold standard for esophageal examination.
Radiation esophagitis is by many authors divided into two forms - acute and chronic    . Acute radiation esophagitis is defined as the onset of esophageal-related symptoms as a response to radiation therapy (RT) within 3 weeks    . Most commonly reported complaints are nausea, odynophagia, dysphagia, and anorexia that can promote significant weight loss   . Pain in the substernal region and discomfort is also seen in many patients, developing on the grounds of inflammatory changes occurring in the esophageal mucosa  . The severity of the associated features strongly correlates with the radiation dose (more pronounced signs are seen with higher doses), a more advanced tumor stage, increased age, and the presence of adjuvant chemotherapy (bleomycin, vincristine, cyclophosphamide, actinomycin, and daunorubicin)    . Some patients may not be able to swallow any food and thus require a feeding tube and/or total parenteral nutrition . On the other hand, chronic radiation esophagitis occurs when at least three months pass from RT to the onset of the signs of the ailment, but the majority of patients report around 6-12 months   . The formation of esophageal strictures from fibrotic changes is the main factor for the development of symptoms in these patients, most important being progressive dysphagia, associated swallowing difficulties, and impaired mobility of the esophagus  .
The initial diagnosis of radiation esophagitis is made through a properly obtained patient history. Physicians must identify prior radiation therapy (implying that information about the underlying illness must also be collected) and a distinction between acute and chronic can be made based on the onset, course, and progression (as well as severity) of findings. The physical examination should focus on excluding oral candidiasis (through inspection of the oral cavity), recurrence of the primary disease (by palpating proximal lymph nodes) and aspiration pneumonia (through lung auscultation) . Although the condition can be identified solely on clinical grounds, imaging studies should be employed to solidify suspicion . Barium swallowing test is useful for detecting strictures and abnormal peristalsis, computed tomography (CT) is indicated for evaluation of disease recurrence and detection of a possible fistula, but endoscopy is regarded as the gold standard for esophageal assessment  . In addition to strictures, typical findings on endoscopy include erosions, erythema, ulceration, and even hemorrhage, but the severity of esophageal damage may not always correlate with reported symptoms  . Histology can be useful, particularly when opportunistic infections compromise the diagnosis, showing chronic inflammatory changes and extensive fibrosis  .