Radiation-Associated Chronic Dysphagia Assessment by Flexible Endoscopic Evaluation of Swallowing (FEES) in Head and Neck Cancer Patients: Swallowing-Related Structures and Radiation Dose-Volume Effect.

Purpose We aimed to restore dose-volume parameters of swallowing-related structures (SRSs) by evaluating long-term swallowing dysfunctions after radiotherapy (RT) in head and neck cancer patients (HNCPs). Materials and Methods Head and neck cancer patients whose pharyngeal region was involved in RT portal and treated with definitive RT/chemoradiotherapy (CRT) were included in the analyses. Patients underwent objective swallowing assessment by flexible endoscopic evaluation of swallowing (FEES). Volumes of SRSs that received 55 Gy (V-55) (mean dose [D-mean]) were evaluated according to the dose-volume histograms of each patient. For every SRS, optimal dose-volume cut-off values were determined by receiver operating characteristic curve analysis. Results Fifty-five patients at a median 20 months (range, 12-26 months) after their treatments were evaluated. There was a strong negative correlation between FEES scores and dose-volume parameters of SRS (r <= -0.5, P < .0001). According to our results, middle pharyngeal constrictor (MPC) and inferior pharyngeal constrictor (IPC) had a D-mean > 57 Gy, base of tongue (BOT) D-mean > 50 Gy, supraglottic larynx (SGL) and glottic larynx (GL) D-mean > 55 Gy, and cervical esophagus (CE) D-mean > 45 Gy. MPC V-55 > 70%, IPC V-55 > 50%, BOT V-55 > 65%, CE V-55 > 40%, and SGL and GL V-55 > 50% were significant predictors for dysphagia. Conclusion It was found that dysphagia correlates strongly with dose-volume parameters of SRSs. IPC, SGL, and CE were found to be structures significantly associated with dysphagia.