Clinical utility of a functional lumen imaging probe in management of dysphagia following head and neck cancer therapies

Background and aims Chemoradiotherapy for head and neck cancer (HNC) with/without laryngectomy commonly causes dysphagia. Pharyngoesophageal junction (PEJ) stricturing is an important contributor. We aimed to validate a functional lumen imaging probe (the EndoFLIP system) as a tool for quantitating pretreatment PEJ distensibility and treatment-related changes in HNC survivors with dysphagia and to evaluate the diagnostic accuracy of EndoFLIP-derived distensibility in detecting PEJ strictures. Methods We studied 34 consecutive HNC survivors with long-term (>12 months) dysphagia who underwent endoscopic dilation for suspected strictures. Twenty non-dysphagic patients undergoing routine endoscopy served as controls. PEJ distensibility was measured at endoscopy with the EndoFLIP system pre- and post-dilation. PEJ stricture was defined as the presence of a mucosal tear post-dilation. Results PEJ stricture was confirmed in 22/34 HNC patients (65%). During distension up to 60mmHg, the mean EndoFLIP-derived narrowest cross-sectional area (nCSA) in HNC patients with strictures, without strictures, and in controls were 58mm ² (95% confidence interval [CI] 22 to 118), 195mm ² (95%CI 129 to 334), and 227mm ² (95%CI 168 to 316), respectively. A cutoff of 114mm ² for the nCSA at the PEJ had perfect diagnostic accuracy in detecting strictures (area under the receiver operating characteristic curve=1). In patients with strictures, a single session of dilation increased the nCSA by 29mm ² (95%CI 20 to 37; P <0.001). In patients with no strictures, dilation caused no change in the nCSA (mean difference 13mm ² [95%CI -4 to 30]; P =0.13). Conclusions EndoFLIP is a highly accurate technique for the detection of PEJ strictures. EndoFLIP may complement conventional diagnostic tools in the detection of pharyngeal outflow obstruction.