Validation of the Korean Version of the Minneapolis-Manchester Quality of Life Instrument for Childhood Cancer Survivors

Purpose: Remarkable improvements in survival of children with cancer have resulted in a growing population of Korean childhood cancer survivors. However, long-term survivors are at risk for developing a broad spectrum of adverse outcomes. Therefore increasing emphasis is now being placed on health-related quality of life (HRQL) of Korean childhood cancer survivors. The Minneapolis-Manchester Quality of Life Instrument (MMQL) is a standardized patient self-report instrument designed to assess HRQL in childhood cancer survivors. In order to create an appropriate scale for the HRQL assessment of Korean childhood cancer survivors, the Korean version of MMQL-Youth Form (YF) (8 to 12 years) and MMQL-Adolescent Form (AF) (13 to 20 years) were cross-culturally adapted into Korean and its reliability and validity were evaluated.

Patients and Methods: The translation procedure followed the standard Functional Assessment of Chronic Illness Therapy (FACIT) translation methodology. The patients who were given the diagnosis of cancer participated in this study. The subjects consist of 4 groups, which are 8–12 and 13–20 aged patients undergoing treatment after the diagnosis of cancer, and 8–12 and 13–20 aged patients who were more than 1 year after terminating treatment. Factor analysis uses the pattern of inter-item correlations to produce clusters of items that have substantial correlations with one another. The stability was tested by readministering the MMQL to a subset of participants of each group after a 2-week interval. Cronbach’s coefficient alpha was used to assess the internal consistency. Discriminate validity was determined by comparing children undergoing treatment with children off therapy. Construct validity was conducted by comparing the patient responses of MMQL with their mothers responses of Child Health Questionnaire Parent version (CHQ-PF50).

Results: The MMQL-YF were administered to 63 children undergoing treatment and their mothers and 66 off-therapy cancer survivors and their mothers. The MMQL-AF were administered to 60 children undergoing treatment and their mothers and 85 off-therapy cancer survivors and their mothers. Test-retest reliability of MMQL-YF (Cronbach’s a=0.76) and MMQL-AF (Cronbach’s a=0.82) demonstrated that both instruments were stable in all questionnaires. For internal consistency reliability, overall Cronbach’s alpha coefficient was 0.86 for the Korean version of MMQL–YF and 0.90 for the Korean version of AF. These results indicate that the items constituting the MMQL-YF and MMQL-AF were consistent internally. The MMQL-YF and MMQL-AF were able to discriminate between children undergoing treatment and off-therapy cancer survivors. The scales of MMQL-YF and MMQL-AF were highly correlated with similar CHQ-PF50 domains.

Conclusion: This study provides evidence for the reliability and validity of the Korean version of MMQL-YF and MMQL-AF as a comprehensive, multidimensional self-report instrument for measuring HRQL among Korean childhood cancer survivors.