Independent Validation of the Japanese Version of the EORTC QLQ-C15-PAL for Patients With Advanced Cancer.

Abstract

Although the psychometric properties of the Japanese version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative Care (EORTC QLQ-C15-PAL) have been examined previously, that study had several limitations, for example, small sample size. To examine the validity and reliability, including test-retest reliability, of the Japanese version of EORTC QLQ-C15-PAL for cancer patients with metastasis or recurrence. A cross-sectional anonymous questionnaire was administered to cancer patients who were being treated on an oncology inpatient ward, in an oncology outpatient clinic, and in seven inpatient palliative units in Japan, from August 2007 to March 2008. Data from a total of 312 cancer patients were analyzed. The proportion of missing values was less than 4% for all items. The factor structure was reproduced identically with the original EORTC QLQ-C15-PAL, English version. The correlation of subscales showed a reasonable matrix. Cronbach's alpha coefficients were 0.76 to 0.86, and intraclass correlation coefficients, which indicate test-retest reliability, ranged from 0.52 to 0.77. All subscales, especially physical functioning, fatigue, and pain, were significantly correlated with self-reported Eastern Cooperative Oncology Group performance status. The Japanese version of EORTC QLQ-C15-PAL has sufficient validity, acceptable reliability, and feasibility for patients with advanced cancer.