Linguistic Validation of the M. D. Anderson Symptom Inventory in Persian-Speaking Iranian Cancer Patients.

CONTEXT: Various symptoms frequently affect cancer patients' quality of life. Appropriate assessment of these symptoms provides valuable data for cancer management.

OBJECTIVES: This study aimed to validate the Persian version of the M. D. Anderson Symptom Inventory (MDASI-P).

METHODS: This cross-sectional study was conducted at four cancer treatment centers in two cities in Iran. Breast cancer and colorectal cancer patients aged 18 years and older were consecutively included in the study. The standard forward-backward translation method was applied. Patients completed the MDASI-P along with the previously validated Persian version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30). Construct validity (factor analysis), criterion validity (against the EORTC QLQ-C30), and reliability (Cronbach's alpha) were analyzed.

RESULTS: A total of 146 breast cancer and 94 colorectal cancer patients were studied. Factor analysis for the symptom severity items resulted in a three-factor solution, further reduced to a two-factor solution: general symptoms and gastrointestinal symptoms. Correlation of the MDASI-P symptom severity items with corresponding EORTC QLQ-C30 symptom items (r = 0.48-0.75) and MDASI-P interference items with corresponding EORTC QLQ-C30 functioning domains (r = -0.46 to -0.23) supported the criterion validity. Cronbach's alpha was 0.90, 0.88, and 0.77 for the total questionnaire, symptom severity items, and the interference subscale, respectively.

CONCLUSION: The MDASI-P is a feasible, valid, and reliable instrument for evaluation of symptoms in Persian-speaking cancer patients and can be used to improve symptom management in these patients.