Development of the Japanese version of the Minneapolis-Manchester Quality of Life Survey of Health - Adolescent Form (MMQL-AF) and investigation of its reliability and validity

Background: There are very few reliable and valid measures in Japan assessing health-related quality of life (HRQOL) in children with cancer. The present study aimed to develop a Japanese version of the Minneapolis-Manchester Quality of Life Survey of Health Adolescent Form (MMQL-AF), which is a measure for assessing the HRQOL of childhood cancer survivors, and investigate its reliability and validity. Methods: Participants were 141 children with cancer who had been off therapy for more than one year and 183 healthy controls. The reliability and internal consistency of the measure were assessed through test-retest methods using Cronbach's coefficient alpha and intra-class correlation coefficients (ICCs). For validation of the measure, factorial validity, concurrent validity using the Japanese version of PedsQL 4.0 Generic Core Scales (PedsQL-J), and discriminant validity using comparisons between children with cancer and healthy controls were investigated. Results: Of the 46 items in the original version, 44 items were determined to comprise the Japanese version of the MMQL-AF. Cronbach's coefficient alphas for each subscale were high ranging from 0.83 to 0.89. Test-retest reliability ranged between ICC 0.79 to 0.96. Investigation of concurrent validity using the PedsQL-J demonstrated strong correlations in physical functions and moderate correlations for other factors. A significant difference was observed between children with cancer and healthy controls. Conclusions: Thus, the Japanese version of the MMQL-AF served as a self-evaluation questionnaire that allowed for practical, comprehensive, and multidimensional measurement of HRQOL specific to childhood cancer survivors.