Psychometric validation of Chinese version of the immunotherapy of the M.D. Anderson Symptom Inventory for Early-Phase Trials module in a multi-cancer cohort

Objective: The Immunotherapy of the M.D. Anderson Symptom Inventory for Early-Phase Trials module (MDASI-Immunotherapy EPT) was initially developed to assess the severity of symptoms in tumor patients undergoing immunotherapy. However, in the application of this scale, it was observed that the scale did not cover the wide range of symptoms patients reported. Therefore, the scale was revised to reflect such symptoms more comprehensively based on previous studies and expert advice. Methods: A comprehensive approach was employed to identify symptoms associated with immunotherapy, encompassing a systematic literature review, semi-structured interviews with clinicians and patients, Delphi methodology, and cognitive interviews. Based on item analysis and assessments of reliability and validity, 15 immunotherapy-specific items were ultimately selected for inclusion in the revised MDASI scale. Results: Through systematic literature review, semi-structured interviews, Delphi consensus, and cognitive interviews, 17 new immunotherapy-specific symptoms were identified. Following item analysis in Study 2.1 (n=396), 9 items were excluded, resulting in a final 34-item scale comprising 13 core symptoms, 15 immunotherapy-specific items, and 6 interference items. Exploratory factor analysis in an independent sample (Study 2.2, n=418) revealed a 6-factor structure (skin symptoms, digestive system symptoms, cardiac symptoms, hepatobiliary system symptoms, extremity edema and musculoskeletal symptoms, pain and fever dimensions) explaining 77.59% of the total variance. The revised MDASI-Immunotherapy EPT demonstrated excellent internal consistency reliability, with Cronbach's alpha values of 0.917 for the core subscale, 0.878 for the immunotherapy module, and 0.910 for the interference subscale. Criterion validity analysis using Spearman's correlations revealed significant associations with FACT-G physical well-being domain (ρ = 0.551-0.674, p < 0.01). Subgroup analyses confirmed consistent psychometric properties across urban and rural populations and across major cancer types. Conclusions: The modified MDASI-Immunotherapy EPT is a valid, reliable, and sensitive tool for measuring symptomatic toxicity in patients receiving immunotherapy.