Assessment of change of quality of life in terminally ill patients under cancer pain management using the EORTC Core Quality of Life Questionnaire (QLQ-C30) in a Korean sample

Abstract

Objective: The European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ-C30) is composed of 5 multi-item function scales and 9 symptom scales. The Korean EORTC QLQ-C30 was drawn up by the EORTC itself. However, its validity and reliability in the palliative care has not been reported. The aim of this study was to evaluate the practicality, reliability, and validity of the Korean EORTC QLQ-C30 in terminally ill patients under cancer pain management.

Methods: The study was conducted from March 2003 to February 2004. The main sample consisted of 159 patients with cancer-related pain during the past week. To assess the severity and impact of pain, the patients completed the Korean version of the Brief Pain Inventory. We enrolled the patients with substantial pain who rated their worst pain as 5 or higher. The participants reported their worst pain of the previous week using the Brief Pain Inventory and were given the EORTC QLQ-C30 to fill out. Two weeks later, the patients were asked to complete the questionnaire a second time while they were on cancer pain management.

Results: The questionnaire was well accepted among terminally ill cancer patients. The scale reliability was very good [Cronbach's alpha: 0.80-0.91 (before treatment), 0.81-0.92 (on treatment)], except for cognitive function. In the initial measure of the QLQ-C30 for each patient, clinical validity was found for all the functional scales using the Eastern Cooperative Oncology Group Performance Status Scale. Ninety-eight patients had improved cancer pain severity, 17 patients had deteriorated cancer pain, and 29 patients had unchanged pain. The differences in QLQ-C30 scores were compared between the improved and nonimproved cancer pain group. Statistically significant between-group differences over time were observed for the scales of global quality of life, fatigue, pain, nausea, and sleep disturbance.

Conclusions: Cronbach's alpha coefficient to judge internal consistency was very good except for cognitive functioning. The Korean QLQ-C30 has a strong validity in functional scales. Global quality of life, pain, fatigue, nausea, and sleep disturbance were improved after cancer pain management. These results support that the QLQ-C30 is a reliable and valid measure of quality of life in Korean cancer patients receiving cancer pain management. We consider that the QLQ-C30 can be used effectively in the palliative care settings in order to assess the effects of cancer pain management on quality of life of advanced-stage cancer patients.