Validation of the distress thermometer worldwide: state of the science

Background: The distress thermometer (DT) has been used in psycho-oncology research across the globe and has been recommended as a clinical tool to be used routinely in cancer settings to detect clinically significant distress. We sought to characterize the translation and validation of the DT in cancer patients in different countries and cultures and summarize how the translated versions function to detect clinically significant distress.

Methods: An electronic mail survey was sent to the members of the International Psychosocial Oncology Society Federation of Psycho-Oncology Societies and electronic searches of English language databases were conducted to identify translations of the DT and studies designed to validate these translations.

Results: Our efforts yielded a total of 21 non-English translations of the DT; 18 of these were validated in studies designed for that purpose. A variety of instruments were used in receiver operating characteristic curve analysis to derive an optimal cut-off score indicative of clinically significant distress. Cut-off scores varied by language, country, and clinical setting and to sample characteristics. In the majority of studies, a score of 4 maximized sensitivity and specificity relative to an established criterion.

Conclusions: These findings provide a broad, international perspective on the current state of psychosocial screening using the DT. Findings also demonstrate widespread awareness of the need for psychological and social support of persons diagnosed with and treated for cancer.