A pilot study of the translation, cultural adaptation and validation of the EORTC head and neck cancer quality of life questionnaire module (QLQ-H&N35) for use in Japan

Development of the Japanese version of the European Organisation for Research and Treatment of Cancer (EORTC) quality of life questionnaire (QLQ)-head and neck 35 (H&N35) module for use in Japan. Phase 1: The First Intermediary Japanese version was produced according to the EORTC Quality of Life (QOL) Unit translation project guideline. The Second Intermediary version was a result of the backward translation project and two peer-to-peer discussion settings by health care professionals related to the project. Phase 2: Focus group discussions with team members and semi-structured interviews with 108 participants to produce the final Japanese version. Our cultural-adaptation and validation yielded scores that are reliable by internal consistency (Cronbachʹs alpha) and the validation results showed acceptable correlation results by Pearsonʹs Product Moment Correlation Coefficient (r). The questionnaire was well accepted and the response rate was high (93.9%). Convergent validity was moderate to high (from r = 0.55 to 0.97, P < 0.01) and discriminant validity was low; Cronbachʹs α coefficients of most scales had good reliability (α ≥ 0.70), except that of pain scale. In Japan, however, some correlation patterns between scales differed from that in the original European countries and cultures. The use of both qualitative and quantitative methods was important in developing the Japanese version of the QLQ-H&N35 module. We conclude that the Japanese version has good psychometric validity, thus it is recommended for further study to assess health-related quality of life (HRQOL) in Japanese head and neck cancer patients.