Acute esophagitis is common in thoracic radiation. It can be severe and permanent, causing dysphagia and strictures requiring repeated dilation. Patients with severe esophagitis may require PEG tube and treatment interruptions. Patients with thoracic cancers have a relatively shorter life expectancy, therefore the focus of most studies has been on acute toxicity. Late toxicities do occur and have been seen in a variety of treatment sites including lung, esophagus and breast treatment. Late complications include stricture, fistula (rare), necrosis (rare), dysphagia, dysmotility, and odynophagia.
The esophagus is challenging to delineate on CT imaging. Contrast is important in identifying the esophagus which should take the form of a thickened slurry. The esophagus has a relatively uniform circumference but appears somewhat variabible on CT scan.
There is no consensus for optimum dose-volume-fraction parameters. Washington University demonstrated grade 3-5 toxicity (RTOG Scoring Criteria) with Dmax greater than 34 Gy with concurrent chemotherapy. V55 was not shown to be significant. China reported a dose greater than 60 Gy with concurrent chemotherapy was a significant factor for esophageal acute and late toxicity. Hyperfractionation, concommitant boost, concurrent chemotherapy and advaning age all correlate with increased esophageal toxicity. Acute esophageal toxicity was the greatest predictor of late toxicity. The incidence of daily fractionated RT alone is low, but esophageal toxicity increases significantly when chemotherapy is added, in particular, gemcitabine plus daily RT has reported toxicity rates as high as 49% compared to radiation alone toxicity of about 1%.
Risk factors include more aggressive radiotherapy regimens, concurrent chemotherapy, increasing age, pre-existing dysphagia, increasing nodal stage and length of esophagus irradiated. There may be a benefit to adding amifostine to the treatment, but this has not been confirmed in in the Phase III RTOG 9801 trial.
There are no QUANTEC recommended strict dose/volume limits for the esophagus. In many situations it is not possible to limit dose to the esophagus due to tumor location, particularly in locally advanced lung cancers. RTOG 0617 recommends that the mean esophagus dose be kept to < 34 Gy. Note that this is not a dose limit on the protocol.