The development of a financial toxicity patient‐reported outcome in cancer: The COST measure

Considering patients' experience is essential for optimal decision-making. However, despite increasing recognition of the impact of costs on oncology care, there is no patient-reported outcome measure (PROM) that specifically describes the financial distress experienced by patients.

The content for a comprehensive score for financial toxicity (COST) was developed with a stepwise approach: step 1) a literature review and semistructured, qualitative interviews with patients for content generation; step 2) patients' assessment of the items for importance to their quality of life; step 3) pilot testing assessing interitem (IIC) and item-total (ITC) correlations to identify redundancy (Spearman rho, > 0.7) and statistically unrelated content (P > .05); and step 4) exploratory factor analysis. Sociodemographic data were collected.