The objective of this study was to test the reliability and validity of the Japanese version of the European Organization for Research and Treatment of Cancer (EORTC) Colorectal Cancer-Specific Quality of Life Questionnaire (QLQ-CR38).
The questionnaire was tested among 109 colorectal cancer patients on several occasions. The timing was prior to treatment with radiotherapy or chemotherapy, during treatment and 3 months following the second assessment. For purpose of test–retest reliability, a subgroup of patients completed the QLQ-CR38 1 week following the third assessment.
Multitrait scaling analysis confirmed the hypothesised scale structure of both the function scales and the symptom scales except female sexual problem scale. Cronbach’s alpha coefficients for seven of the nine scales exceeded the 0.7 criterion at one or both assessments. The test–retest reliability for all scales except three symptom scales was 0.67 or higher. On the basis of known-groups comparisons, four of 46 comparisons distinguished between patients differing in disease stage, initial and on-treatment performance status and presence or absence of a stoma. Additionally, these scales detected change over time as a function of change in performance status and treatment-induced change.
These preliminary results suggest that the Japanese EORTC QLQ-CR38 may be a reliable and valid supplementary measure of quality of life in colorectal cancer patients.