Non–Small Cell Lung Cancer Symptom Assessment Questionnaire: Psychometric Performance and Regulatory Qualification of a Novel Patient-Reported Symptom Measure

BACKGROUND: The Non–Small Cell Lung Cancer Symptom Assessment Questionnaire (NSCLC-SAQ) was developed to incorporate the patient's perspective into evaluation of clinical benefit in advanced non–small cell lung cancer trials and meet regulatory expectations for doing so. Qualitative evidence supported 7 items covering 5 symptom concepts. OBJECTIVE: This study evaluated measurement properties of the NSCLC-SAQ's items, overall scale, and total score. METHODS: In this observational cross-sectional study, a purposive sample of patients with clinician-diagnosed advanced non–small cell lung cancer, initiating or undergoing treatment, provided sociodemographic information and completed the NSCLC-SAQ, National Comprehensive Cancer Network/Functional Assessment of Cancer Therapy Lung Symptom Index (FLSI-17), and a Patient Global Impression of Severity item. Rasch analyses, factor analyses, and assessments of construct validity and reliability were completed. RESULTS: The 152 participants had a mean age of 64 years, 57% were women, and 87% where White. The majority were Stage IV (83%), 51% had an Eastern Cooperative Oncology Group performance status of 1 (32% performance status 0 and 17% performance status 2), and 33% were treatment naïve. Rasch analyses showed ordered thresholds for response options. Factor analyses demonstrated that items could be combined for a total score. Internal consistency (Cronbach α = 0.78) and test–retest reliability (intraclass correlation coefficient = 0.87) were quite satisfactory. NSCLC-SAQ total score correlation was 0.83 with the National Comprehensive Cancer Network/Functional Assessment of Cancer Therapy Lung Symptom Index-17. The NSCLC-SAQ was able to differentiate between symptom severity levels and performance status (both P values < .001). CONCLUSIONS: The NSCLC-SAQ generated highly reliable scores with substantial evidence of construct validity. The Food and Drug Administration's qualification supports the NSCLC-SAQ as a measure of symptoms in drug development. Further evaluation is needed on its longitudinal measurement properties and interepretation of meaningful within-patient score change. (Curr Ther Res Clin Exp. 2021; 82:XXX–XXX)