Psychometric Analysis of a Persian Version of the European Organization for Research and Treatment of Cancer OG25 Quality of Life Questionnaire in Oesophagogastric Cancer Patients

Background: Health-related quality of life (HRQL) is a fundamental outcome in oncology patients and quality of life (QOL) assessment requires clinically relevant questionnaires. The purpose of this study was translation and definition of measurement properties and the clinical validity of Quality of Life Questionnaire (QLQ)-OG25 module in Persian patients with oesophagus, oesophagogastric junction (OGJ) or gastric cancers. Materials and Methods: The translation procedure followed European Organization for Research and Treatment of Cancer (EORTC) guidelines. Both EORTC QLQ-OG25 and a core questionnaire (EORTC QLQ-C30) were administered to patients with oesophagus (150), OG junction (93) and gastric (32) cancer undergoing multi-modal treatments. Convergent and discriminant validity, Cronbach's alpha coefficient and known-groups comparisons were used to examine reliability and validity. Results: In all, 275 patients (mean age 62 years) completed both questionnaires. Compliance rate was high and the questionnaire module was well accepted. We found good reliability for multi-item subscales of QLQ-OG25 (Cronbach's alpha coefficients 0.76-0.89). About 73% had TNM staging and scales distinguished between clinically distinct groups of patients. However, patients in palliative group experienced compromised functional status and worse treatment-associated symptoms than those in the potentially curative group. Test-retest scores were consistent. Multi-trait scaling analysis demonstrated good convergent and discriminant validity. Conclusions: Overall, the Persian version of QLQ-OG25 demonstrated psychometric and clinical validity that supports its application as a supplement to the original tool (EORTC QLQ-C30) when assessing HRQL in patients with upper-gastrointestinal (GI) cancer both in curative and palliative phases.