Quality of life in breast cancer adjuvant therapy: validation and pilot testing of a combination of questionnaires

Quality of life assessment is important in many breast cancer trials. The validity of quality of life data is crucial. It is now well recognized that standardized questionnaires are preferable. However, even the choice of the most well-tested questionnaire does not guarantee content validity and that the relevant issues are included. This article describes the documentation of content validity and the pilot testing of questionnaires for breast cancer adjuvant trials. To accompany two standardized questionnaires (EORTC QLQ-C30 and HADS), we constructed a study-specific questionnaire to cover the topics identified in a literature review. Patient interviews largely confirmed the selection of content. In pilot testing, the questionnaires were well accepted. Evidence of clinical validity was found. The procedures described are suggested as a minimum standard for content validity documentation and feasibility testing of quality of life questionnaires for clinical trials.