Introduction and validation of the open symptom framework: a public domain modular framework for patient-reported measurement of symptoms related to cancer and its treatment.

Purpose: We provide an initial description and validation of some public domain patient-reported outcome (PRO) items to assess cancer symptom burden to address immediate barriers to symptom assessment use in clinical practice and facilitate future research.

Methods: We created the Open Symptom Framework (OSF), a flexible tool for clinical cancer-related symptom assessment. The items comprise six components: recall period, concept, symptom, qualifier(s), a definition, and a 5-point Likert-type response. We recruited patients receiving cancer therapy in the United States and United Kingdom. We assessed external construct validity by comparing OSF scores to the PRO-CTCAE measure and assessed reliability, scalability, dimensionality, and item ordering within a non-parametric item response theory framework. We tested differential item functioning for country, age, gender, and level of education.

Results: We developed a framework alongside clinical and psychometric experts and debrieifed with 10 patients. For validation, we recruited 331patients. All items correlated with the PRO-CTCAE equivalents (r = 0.55-0.96, all p < 0.01). Mokken analysis confirmed the scalability and unidimensionality of all symptom scales with multiple items at the scale (Ho = 0.61-0.75) and item level (Hi = 0.60-0.76). Items are interpreted consistently between demographic groups (Crit = 0 for all groups).

Conclusion: The public domain OSF has excellent psychometric properties including face, content, and criterion validity and can facilitate the development of flexible, robust measurements to fulfil stakeholder need. The OSF was designed specifically to support clinical assessment but will function well for research. Further work is planned to increase the number of symptoms and number of questions per symptom within the framework.