Comparison of cervical esophagus dose-volumes for three radiotherapy techniques for head and neck cancer

PURPOSE: This study compares the radiation dose-volume of the cervical esophagus during head and neck radiotherapy using three different techniques. METHODS: Treatment plans of 58 patients from 3/04 to 1/06 treated with bilateral head and neck radiotherapy were analyzed retrospectively. A comparison of the cervical esophagus dose with three-field 3D conformal RT (3DRT, n=34), whole-field IMRT (WF-IMRT, n=12), and half-beam IMRT (HB-IMRT, n=12) was performed. The volumes of esophagus receiving > or =50Gy (V50), > or =54Gy (V54) and > or = 60Gy (V60) and lengths receiving circumferential dose > or = 50Gy (L50) and > or = 54Gy (L54) were evaluated. RESULTS: Maximum dose, V54 and L54 were greater for the first 2cm and entire cervical esophagus with WF-IMRT than HB-IMRT or 3DRT. In patients requiring a high match, WF-IMRT was associated with a greater maximum dose, V54 and L54 than HB-IMRT and 3DRT (p<0.05). In the low match group, WF-IMRT was associated with a greater V54 and L54 (p<0.05). Low neck disease, low primary site, and definitive radiotherapy were associated with increased irradiation of the esophagus. CONCLUSION: Treatment of the lower neck with IMRT is associated with increased irradiation to the cervical esophagus, and dose constraints should be included to reduce toxicity.