Cultural adaptation and validation of the Korean version of the EORTC QLQ-CR29 in patients with colorectal cancer
We aimed to evaluate the psychometric properties of the Korean version of the European Organization for Research and Treatment of Cancer (EORTC) Colorectal Cancer-Specific Quality of Life Questionnaire (QLQ-CR29), based on a sample of patients with colorectal cancer. A total of 123 patients treated for colorectal cancer participated in the validation study. Test–retest reliability was assessed using intra-class correlations from a random sample. Internal consistency reliability was estimated using Cronbach’s α coefficient. Convergent and discriminant validity was analyzed with multi-trait scaling. Clinical validity was assessed in terms of clinical differences using known-group comparisons. Concurrent validity was determined by correlations with the EORTC QLQ-C30, which was a generic core questionnaire to evaluate issues common to different cancer sites and treatments. The test–retest, administered to 35 patients, showed acceptable reproducibility (0.62–1.00) except the constipation scale of the QLQ-C30 (0.43). Cronbach’s α coefficient (0.70–0.87) exceeded the 0.7 criterion. Multi-trait scaling analysis showed that multi-item scales met standards of convergent and discriminant validity. The known-group comparisons showed quality of life (QOL) differences between groups of patients based on tumor location, receipt of neoadjuvant therapy, and with/without a stoma. Correlations between the scales of the QLQ-CR29 and QLQ-C30 were low in most areas, whereas correlations in several areas with related content were higher. This study shows that the Korean version of the EORTC QLQ-CR29 is a reliable and valid tool for measuring QOL, as determined by application to a sample of Korean colorectal cancer patients.