Measurement Properties of Patient-Reported Outcome Measures in Radiotherapy-Induced Trismus

Objectives: To assess the measurement properties of available patient-reported outcome measures (PROMs) relevant to Radiotherapy-Induced Trismus (RIT) in head and neck cancer patients.
Methods: Systematic electronic searches were performed in MEDLINE and EMBASE databases to identify validation studies evaluating measurement properties of PROMs measuring RIT based on predefined eligibility criteria, up to January 2018. Two reviewers independently rated the methodological quality of included studies, utilizing the consensus-based standards for the selection of health status measurement instrument (COSMIN)
checklist. Strengths of evidence for measurement properties were then summarised based upon pre-defined criteria.
Results: Only one of the 280 retrieved studies was deemed fit for inclusion. The study, which is relevant to the Gothenburg Trismus Questionnaire (GTQ), was assessed and found to have good methodological quality of measurement properties except for reliability, which was poor. There was moderate level of evidence supporting GTQ’s internal consistency, content validity, structural validity and hypothesis testing. The evidence for test-retest reliability remains unknown in the population of interest.
Conclusions: The GTQ is the only PROM, in the field of RIT, showing some good measurement properties and it may therefore represent a useful instrument for the assessment of RIT in head and neck cancer patients. However, further validation studies are needed with respect to the reliability, measurement error and responsiveness of this instrument.