Thresholds of Quantitative Swallowing Measures Following Intensive Prophylactic Therapy in Head and Neck Cancer

This retrospective, case-controlled study sought to identify salient features of swallowing physiology in head and neck cancer (HNC) patients and the threshold for features associating with increased dysphagia severity or decreased functional status. Quantitative measures of videofluoroscopic swallow studies (VFSS) were taken during three graduating liquid boluses and a paste bolus. Fifteen HNC subjects that received high frequency swallowing exercises (2 - 5 weekly sessions) during (chemo)radiation were compared pre- and(n = 15) or normal (n = 15) swallowing. HNC subjects were also stratified to compare those attending only pre- and(n = 8) to those also returning with dysphagia complaints 2 months to 3 years post-treatment (n = 7). Atypical and extreme values of concern (i.e., values anticipated to have a negative impact on function) were isolated by comparing frequency counts for each quantitative measure between HNC pre- and/normal subjects. Correlation of quantitative measures with standardized measures of dysphagia severity and functional status were determined at pre-, <6w>post-, and 2m – 3y post-treatment. Thresholds were established for all associated measures based on atypical limits. Typical values for pharyngoesophageal segment (PES) opening duration (PESop) and extent (PESmS), as well as hyoid to larynx approximation (HL), were maintained or increased for all HNC subjectsHowever, persistent toxicities were evidenced by a high frequency of increased area of the posterior pharyngeal wall at rest, increased epiglottic thickness, and impaired epiglottic inversion at– 3y post-treatment. Further, >25% of the group had increased pharyngeal constriction ratio (PCR), bolus clearance ratio (BCR), and Penetration Aspiration Scale scores, markedly with small liquid boluses. Dysphagia severity and functional status repeatedly associated with increased time to aryepiglottic closure, PCR, and BCR at pre-, <6w>post-, and 2m – 3y post-treatment. Infrequent values of concern for PESmS, PESop, and HL indicate positive effects of an intensive prophylactic program. However, results wholly demonstrate the program may not sufficiently supersede toxicities for select patients, particularly with small boluses. Further research confirming and utilizing threshold values in a larger sample is needed.