Dorsal vagal complex of the brainstem: conformal avoidance to reduce nausea.

PURPOSE: To investigate the role of dose to the dorsal vagal complex (DVC) as an emetic stimulus in head-and-neck cancer patients treated with intensity modulated radiation therapy but without chemotherapy. METHODS AND MATERIALS: Seventy consecutively treated patients were analyzed for factors associated with nausea. The DVC was contoured on treatment planning scans using a previously published template and mean dose to the structure was analyzed for dose response. RESULTS: Nausea occurred in 26 of 70 patients (37%). Two patients (3%) experienced grade 2 nausea, with the remainder having grade 1 nausea. On univariate analysis, dose to the DVC, age, and T-stage were the only significant predictors of nausea. The highest quartile of dose to the DVC (>3000 cGy) was associated with an incidence of nausea of 67% compared with less than 30% in each of the other 3 quartiles (P = .0255). CONCLUSIONS: Dose to the DVC of the brainstem appears to correlate with radiation-induced nausea and vomiting. Attentive treatment planning efforts can reduce dose to this critical structure and hopefully minimize the risk of nausea.

Factors associated with radiation-induced nausea and vomiting in head and neck cancer patients treated with intensity modulated radiation therapy.

BACKGROUND AND PURPOSE: To investigate factors associated with radiation-induced nausea and vomiting (RINV) in the setting of head and neck intensity modulated radiation therapy (IMRT). MATERIALS AND METHODS: Forty-three patients treated with IMRT for head and neck cancer between 2002 and 2007 comprise the cohort. The majority (79%) were treated with an accelerated altered fractionation scheme, and concurrent chemotherapy was delivered to 23. A retrospective review of factors associated with nausea was performed. RESULTS: Eighteen patients (42%) reported grade 1 acute nausea, and seven patients (16%) reported grade 2 nausea. Factors significant for grade 1-2 nausea on univariate analysis included dose to the dorsal vagal complex of the mid-medulla, younger age, use of a low neck field, and Amifostine use. Only young age retained significance on multivariate analysis. High-grade nausea was associated with use of Amifostine (p=0.003) and concurrent chemotherapy (p=0.015). CONCLUSIONS: In addition to previously recognized emetic factors, young age and radiation dose to the dorsal vagal complex of the brainstem may play a role in development of nausea during head and neck IMRT.