Dose to the inferior pharyngeal constrictor predicts prolonged gastrostomy tube dependence with concurrent intensity-modulated radiation therapy and chemotherapy for locally-advanced head and neck cancer

Background and purpose To determine if dose and/or dose-volume parameters to anatomic swallowing structures are predictive of gastrostomy tube (PEG) dependence from chemotherapy-intensity modulated radiotherapy (IMRT) in locally advanced head and neck cancer (LAHNC). Methods and materials A retrospective study was performed on 141 consecutive patients with LAHNC (squamous cell) treated with definitive chemoIMRT with weekly concurrent carboplatin and paclitaxel. Late dysphagia was assessed by length of PEG requirement. Analysis of IMRT dose was retrospectively performed for critical swallowing structures. Results Approximately 62% of patients required PEG, the majority placed during treatment. Mean and median time for PEG was 7.7 and 4.4 months respectively (range 1.4-43.8). Only IMRT dose to the inferior constrictor was significantly associated with length of PEG. Mean dose (of individual mean doses) was 47 Gy for prolonged PEG use versus 41 Gy for PEG ≤12 months. V₄₀ to the inferior constrictor also correlated with PEG >12 months (p = 0.02) with a mean V₄₀ of 48% versus 41% for PEG ≤12 months. Conclusions IMRT dose to the inferior constrictor correlated with persistent dysphagia requiring prolonged PEG use. Maintaining mean inferior constrictor dose to ≤41 Gy and V₄₀ to ≤41% may help minimize gastrostomy tube dependence.