The clinical application of the 100mL water swallow test in head and neck cancer.

Water swallow tests have been used as to screen patients with neurological dysphagia who are at risk of aspiration. This study examines the clinical utility of the 100mL water swallow test (WST) in head and neck cancer, by measuring its sensitivity and specificity for identifying aspiration and for monitoring swallow performance up to one year following (chemo)radiotherapy. Patients referred for (chemo)radiotherapy were assessed on the WST (n=173) pre-treatment and 3, 6 and 12months post-treatment. Patients failed the test if they coughed or had a wet voice quality post swallow or were unable to finish the task. A Flexible Endoscopic Evaluation of Swallowing was conducted at the same time points, to test for the presence of aspiration. The WST was timed and the number of swallows required was recorded. Sensitivity of the WST for predicting aspiration was >67%, specificity >46%. There was marked deterioration from pre- to 3months post-treatment for the time taken to drink 100mL (p=0.005), but this improved over the first year (p=0.001). Disease characteristics, patient demographics, radiotherapy dose, or treatment volume were not predictors of this improvement. The 100mL WST is a quick and simple assessment for identifying patients with aspiration, post (chemo)radiotherapy. This test is a useful adjunct to a clinical examination, helping to highlight patients who require an instrumental assessment such as videofluoroscopy. Furthermore, quantitative measures can be derived from this test, which can be used as a measure of swallow performance over time.