Qualitative Development and Content Validity of the Non–small Cell Lung Cancer Symptom Assessment Questionnaire (NSCLC-SAQ), A Patient-reported Outcome Instrument

Abstract

PurposeThe purpose of this article was to describe the process and results of the preliminary qualitative development of a new symptoms-based patient-reported outcome (PRO) measure intended for assessing treatment benefit in clinical trials of advanced non–small cell lung cancer (NSCLC). MethodsIndividual qualitative interviews were conducted in adults with NSCLC (Stages I–IV) in the United States. Experienced interviewers conducted concept-elicitation (CE) and cognitive interviews using semistructured interview guides. The CE interview guide was used for eliciting spontaneous reports of symptom experiences along with probing to further explore and confirm concepts. Interview transcripts were coded and analyzed by professional qualitative coders, and were summarized by like content using an iterative coding framework. Data from the CE interviews were considered alongside existing literature and clinical expert opinion during an item-generation process, leading to the development of a preliminary version of the NSCLC Symptom Assessment Questionnaire (SAQ). Three waves of cognitive interviews were conducted to evaluate concept relevance, item interpretability, and structure of the draft items and to facilitate further instrument refinement. FindingsFifty-one subjects (mean [SD] age, 64.9 [11.2] years; 51.0% women) participated in the CE interviews. A total of 1897 expressions of NSCLC-related symptoms were identified and coded in interview transcripts, representing ~42 distinct symptom concepts. A 9-item initial-draft instrument was developed for testing in 3 waves of cognitive interviews with additional subjects with NSCLC (n = 20), during which both paper and electronic versions of the instrument were evaluated and refined. Participant responses and feedback during cognitive interviews led to the removal of 2 items and substantial modifications to others. ImplicationsThe NSCLC-SAQ is a 7-item PRO measure intended for use in advanced NSCLC clinical trials to support medical product labelling. The NSCLC-SAQ uses a 7-day recall period and verbal rating scales. It was developed in accordance with the US Food and Drug Administration’s PRO Guidance and scientific best practices, and the resulting qualitative interview data provide evidence of content validity. The NSCLC-SAQ has been prepared in both paper and electronic administration formats and a tablet computer–based version is currently undergoing quantitative testing to confirm its measurement properties and support US Food and Drug Administration qualification.