Development of a pediatric oncology financial toxicity outcome measure with content and face validity: The Parent-Reported Instrument of Costs and Experiences with financial toxicity (PRICE) measure.

10073 Background: Cancer treatment often leads to adverse financial consequences for patients and families (i.e., financial toxicity, FT). There is no validated measure to quantify FT in pediatric cancer settings, limiting research in this area. Methods: We applied a stepwise approach to measure development consistent with ISPOR guidelines. First, we conducted qualitative concept elicitation interviews with family caregivers of children treated for cancer, 3-24 months following diagnosis. Second, we drafted de novo survey items guided by salient domains and aspects of FT from the interviews. Items were reviewed by a multi-institutional panel of experts in oncology and/or FT-related research, who provided numeric ratings of item relevance for aggregation into content validity index (CVI) scores. Experts also provided free text feedback on clarity and content. Items with CVI < 0.75 were removed or revised by a consensus-based process. The revised item list was organized into a preliminary measure and forward and back translated into Spanish. Finally, we pretested items with a new cohort of caregivers in English and Spanish, through iterative rounds of language-concordant cognitive interviews (3-4 per round). Between each round, we reviewed and revised the survey to optimize comprehension, decision and response processes, and flow. Results: Concept elicitation with 21 caregivers (86% mothers, 47% college-educated, 14% in Spanish) led to the creation of 56 initial survey items across 5 domains of FT: increased household spending, diminished income, household material hardship, psychological distress related to finances, and behaviors in response to FT. The expert panel (n = 11) consisted of 5 providers, 2 clinical social workers, 2 nurse researchers, and 2 non-clinician researchers, with 6 members external to the study institution. CVI was < 0.75 for 13 items; 11 of these were removed and 2 were revised based on free text feedback. Of 43 items with CVI ≥0.75, 9 were removed based on feedback and/or overlap with more highly rated items. Cognitive interviews were held with 19 caregivers (15 in English, 4 in Spanish; 74% mothers, 53% college educated) over 5 iterative rounds. The 36 remaining items were revised and/or removed, and ultimately organized into 16 questions, one of which was added during this phase based on caregiver feedback. In the final round of interviews, participants reported no concerns with content, clarity, or organization in either language. Conclusions: We developed a novel outcome measure with content and face validity to assess FT specifically in pediatric oncology settings. Next steps consist of field testing to evaluate the measure’s psychometric properties and other dimensions of validity. Potential future applications include use as a study endpoint and/or clinical screening tool.