Psychometric properties of the Persian version of the chemotherapy side effects fear scale among Iranian patients with cancer.

Fear of chemotherapy-induced side effects is a major concern among patients with cancer and may affect psychological well-being and treatment adherence. This methodological study aimed to translate, culturally adapt, and evaluate the psychometric properties of the Persian version of the Chemotherapy Side Effects Fear Scale (CheSeFS). The study was conducted from January to April 2024 at the Cancer Institute of Imam Khomeini Hospital Complex in Tehran, Iran, and included 600 patients undergoing chemotherapy. The CheSeFS underwent forward-backward translation and cross-cultural adaptation. Face and content validity, structural validity, convergent and discriminant validity, internal consistency, test-retest reliability, measurement error, a distribution-based MIC estimate, and factors associated with CheSeFS scores were evaluated. All statistical analyses were performed using Jamovi version 2.7.1 and included descriptive statistics, item analysis, exploratory factor analysis, confirmatory factor analysis, reliability and measurement error analyses, convergent and discriminant validity assessment, distribution-based MIC estimation, and regression analysis. Patient and expert evaluations supported face and content validity. Exploratory factor analysis identified a two-factor structure, including Physiological fear and Subjective or Psychological fear, explaining 54.4% of the total variance. Three items were removed during factor analysis, resulting in a final 11-item scale. Confirmatory factor analysis supported model fit, with χ²(df = 43) = 84.2, RMSEA = 0.06, CFI = 0.99, TLI = 0.99, and SRMR = 0.04. Internal consistency was satisfactory, with Cronbach's alpha = 0.89 for the total scale. Measurement error analysis showed an SEM of 1.64 and an MDC95 of 4.56, and the distribution-based MIC estimate was 1.01 points. The Persian 11-item CheSeFS demonstrated satisfactory validity and reliability for assessing chemotherapy-related fear among Iranian patients with cancer.