Cultural adaptation and validation of the Korean version of the EORTC QLQ-CR29 in patients with colorectal cancer.

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.