OBJECTIVE: To identify swallowing-related structures (SRSs) predicting post-radiotherapy dysphagia in oropharyngeal carcinoma patients.
METHODS: Between September 2020 and October 2022, oropharyngeal cancer patients who had completed radiotherapy at least one year before without recurrence or residuals were selected. They underwent flexible endoscopic evaluation of swallowing (FEES) assessments and dysphagia grading. The mean radiation doses delivered to their SRSs were recalculated. The correlation between radiation doses to each SRS and FEES scores was analysed.
RESULTS: Twenty-nine participants, aged 51-73 years, were enrolled. Six patients had received two-dimensional radiotherapy, eight had undergone three-dimensional conformal radiotherapy, and fifteen had received intensity-modulated radiation therapy. Radiation doses to the inferior pharyngeal constrictor, cricopharyngeus and glottic larynx significantly predicted dysphagia for both semisolids (p = 0.023, 0.030 and 0.001) and liquid diets (p = 0.021, 0.013 and 0.002). The esophageal inlet significantly predicted swallowing outcomes for only the liquid diet (p = 0.007).
CONCLUSIONS: This study supports that SRS-sparing during radiotherapy for oropharyngeal cancers improves swallowing outcomes.

OBJECTIVE: 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).
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 (V55) (mean dose [Dmean]) 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 Dmean > 57 Gy, base of tongue (BOT) Dmean > 50 Gy, supraglottic larynx (SGL) and glottic larynx (GL) Dmean > 55 Gy, and cervical esophagus (CE) Dmean > 45 Gy. MPC V55 > 70%, IPC V55 > 50%, BOT V55 > 65%, CE V55 > 40%, and SGL and GL V55 > 50% were significant predictors for dysphagia.
CONCLUSIONS: 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.