Validity of functional patient-reported outcomes in head and neck oncology: A systematic review

Malignancy and treatment effects in head and neck oncology can be devastating to functional aspects of patient life such as swallowing, blinking, speech, salivation, and facial expression. Historically, the subjective nature of patient experience has resulted in difficulty with quantification and measurement of functional outcomes. Patient-Reported Outcomes (PROs) are questionnaires developed with patient input, forming the new gold standard for clinician assessment of subjective functional outcomes. The current review aims to identify and characterize the validation of PROs pertaining to four critical functional outcomes in head and neck oncology: swallowing, speech, dry mouth, and chewing. A literature search was conducted using MEDLINE, EMBASE, and the Cochrane databases for published, English language, peer-reviewed abstracts involving patients ≥ 18 years of age. Of 708 results, 705 were excluded at abstract or full text screening for not meeting inclusion criteria, exclusion of head and neck SCC patients in development, or absence of a functional domain measurement. The three reviewed studies-Xerostomia Questionnaire, Swallowing Outcomes After Laryngectomy, and Edmonton 33-exhibited strong reliability and construct and content validity, though two applied only to individual functional outcomes within specific patient populations receiving radiation or laryngectomy. While many PROs have been developed in head and neck oncology, very few properly employed extensive patient input in the development process. Further work must be committed to increasing head and neck cancer patient input in PRO development, particularly in the functional domains of speech and chewing.