A Systematic Review of the Translation and Validation Methods Used for the National Comprehensive Cancer Network Distress Thermometer in Non-English Speaking Countries

Objective: The National Comprehensive Cancer Network (NCCN) distress thermometer (DT) was developed as a brief screening tool for detecting distress in cancer patients. Conceptually, distress was considered a more acceptable and inclusive term than other psychological terms such as depression or anxiety. It is used extensively in the United States and other English-speaking countries. We aim to describe the translation and validation methods of the DT and describe the recommended cutoff scores used to identify cancer patients experiencing clinically significant distress.

Methods: Nine bibliographic databases were searched using keywords to identify original research studies for non-English speaking countries' cancer patients. Full articles were independently assessed for inclusion and data extraction by two authors.

Results: The review of 4442 articles yielded 39 articles that validated the DT. We identified 20 languages in 25 countries. In all but one country, investigators were able to agree upon a word or phrase that meant distress in their native language that was subsequently validated against standardized instruments. Asian, Middle Eastern and European counties recommended cutoff score of 4 or 5 to identify clinically significant distress; however, European Union countries had a range of 2 to 7.

Conclusions: Use of the translated DT with non-English speaking cancer patients provides a simple and quick tool to identify high distress. Similar to NCCN, the cutoff score of 4 or 5 was suggested by 78% of the studies; however, more studies of different types of cancer and within and among more countries will strengthen a recommended global DT cutoff score.