International evaluation of the psychometrics of health-related quality of life questionnaires for use among long-term survivors of testicular and prostate cancer

Background: Understanding of the physical, functional and psychosocial health problems and needs of cancer survivors requires cross-national and cross-cultural standardization of health-related quality of life (HRQoL) questionnaires that capture the full range of issues relevant to cancer survivors. To our knowledge, only one study has investigated in a comprehensive way whether a questionnaire used to evaluate HRQoL in cancer patients under active treatment is also reliable and valid when used among (long-term) cancer survivors. In this study we evaluated, in an international context, the psychometrics of HRQoL questionnaires for use among long-term, disease-free, survivors of testicular and prostate cancer. Methods: In this cross-sectional study, we recruited long-term survivors of testicular and prostate cancer from Northern and Southern Europe and from the United Kingdom who had participated in two phase III EORTC clinical trials. Participants completed the SF-36 Health Survey, the EORTC QLQ-C30 questionnaire, the QLQ-PR25 (for prostate cancer) or the QLQ-TC26 (for testicular cancer) questionnaires, and the Impact of Cancer questionnaire. Testicular cancer survivors also completed subscales from the Nordic Questionnaire for Monitoring the Age Diverse Workforce. Results: Two hundred forty-two men (66% response rate) were recruited into the study. The average time since treatment was more than 10 years. Overall, there were few missing questionnaire data, although scales related to sexuality, satisfaction with care and relationship concerns of men without partners were missing in more than 10% of cases. Debriefing showed that in general the questionnaires were accepted well. Many of the survivors scored at the upper extremes of the questionnaires, resulting in floor and ceiling effects in 64% of the scales. All of the questionnaires investigated met the threshold of 0.70 for group level reliability, with the exception of the QLQ-TC26 (mean reliability .64) and the QLQ-PR25 (mean reliability .69). The questionnaires were able to discriminate clearly between patients with and without comorbid conditions. Conclusions: The currently available HRQoL questionnaires exhibit acceptable psychometric properties and were well received by patients, but additional efforts are needed to ensure that the full range of survivor-specific issues is assesse