Psychometric Evaluation of Quality of Life Questionnaire in Breast Cancer Women in Iran

Background: Given the importance of quality of life, especially in women with breast cancer, it is essential to have a valid scale to measure their quality of life.Objectives: Therefore, we conducted a study to examine the psychometric properties of the Persian version of the quality of life questionnaire for women with breast cancer within the cultural context of Iranian society. Methods: This methodological study was conducted on 404 women with breast cancer, aged 20 to 60 years, from September 2021 to April 2022 in three cities in Iran. After translating the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30 (version 3) into Farsi and obtaining experts opinions, the content, construct, convergent, and discriminant validity, as well as the reliability of the scale, were assessed using exploratory and confirmatory factor analysis. The construct validity of the scale was investigated through exploratory factor analysis. Results: Through exploratory factor analysis of this scale, a version with 24 questions was confirmed, identifying five dimensions: Psychological symptoms, daily activities, physical problems, physical activity, and social support. Four items were removed due to factor loadings less than 0.3 and the presence of commonalities. In this study, Cronbach s alpha, McDonald s omega, CR, MaxR, and convergent validity coefficients for each factor were greater than 0.7. Conclusions: This study demonstrated that the Persian version of the quality of life questionnaire is a valid and reliable scale within the cultural context of Iranian society, with potential applications in clinical environments.