Cross-cultural adaptation and validation of the French version of the Expanded Prostate cancer Index Composite questionnaire for health-related quality of life in prostate cancer patients

Background Health-related quality of life (HRQoL) has been positioned as one of the major endpoints in oncology. Thus, there is a need to validate cancer-site specific survey instruments. This study aimed to perform a transcultural adaptation of the 50-item Expanded Prostate cancer Index Composite (EPIC) questionnaire for HRQoL in prostate cancer patients and to validate the psychometric properties of the French-language version.