Deglutition preservation after swallowing (SWOARs)-sparing IMRT in head and neck cancers: definitive results of a multicenter prospective study of the Italian Association of Radiotherapy and Clinical Oncology (AIRO)

Background: To investigate changes of objective instrumental measures and correlate with patient reported outcomes (PROs) of radiation-induced dysphagia (RID) after swallowing organs at risk (SWOARs)-sparing IMRT. Methods: Patients (pts) underwent Fiberoptic Endoscopic Evaluation of Swallowing (FEES), Videofluoroscopy (VFS) and M.D. Anderson Dysphagia Inventory (MDADI) questionnaire at baseline, 6 and 12 months after treatment. They were categorized in two groups: MDADI-C >= 80 and MDADI-C < 80. Pharyngeal residue (PR) and penetration (P) or aspiration (A) were considered as surrogate of RID. Results: Between 2016 and 2022 we enrolled 75 pts, 40 (53 %) MDADI-C >= 80 and 35 (47 %) MDADI-C < 80 at baseline. Among MDADI-C >= 80 the mean baseline PR score at FEES was 0,42 rising to 1,36 at 6 months (p = 0,001) and stabilizing to 1,15 at 12 months (p = 0,21); indeed, the mean baseline PR score at VFS was 0,55 rising to 1 at 6 months (p = 0,069) and slightly dropping to 0,7 at 12 months (p = 0,069). Among MDADI-C < 80 the mean baseline PR score at FEES was 0,56 rising to 1,07 at 6 months (p = 0,012) and stabilizing to 1,07 at 12 months (p= 0,99); indeed the mean baseline PR score at VFS was 0,67 rising to 1,19 at 6 months (p = 0,04) and dropping to 0,78 at 12 months (p = 0,04). No correlation was found between PROs and objective measures. Conclusion: Our results show optimal acceptable deglutition preservation from major complications after SWOARs-sparing IMRT by means of low objective scores in both MDADI-C groups. Lack of correlation between PROs and objective measures suggest that referred RID is likely associated to persistence of SWOARs inflammation rather than to a real impairment of function.