RESUMO
INTRODUCTION: Evaluation of quality of life is very important in cancer patients. Esophagus-specific quality of life questionnaire (QLQ-OES18) is a disease-specific questionnaire for assessing quality of life in esophageal cancer (EC). So we aimed to translate and evaluate the reliability and validity of the QLQ-OES18 when applied to Iranian patients. MATERIALS AND METHODS: This study was designed as cross-sectional study on 62 newly confirmed EC in two referral hospital in Tehran, Iran. Reliability of the subscales was evaluated by intraclass correlation coefficients. Pearson's correlations of an item with its own scale and other scales were calculated to assess convergent and discriminant validity. Clinical validity was also evaluated by known-group comparisons. RESULTS: Cronbach's alpha was higher than 0.7 in most subscales. All subscales met the standards of convergent and discriminant validity. Also QLQ-OES18 had discriminatory power for differentiation between patient's groups with different clinical status. CONCLUSION: Our results provide evidences that Persian version of QLQ-OES18 is a valid and reliable questionnaire when applied to a sample of Iranian patients with EC and is recommended for use in clinical research.