The validity and reliability of the Turkish version of the University of Washington Quality of Life Questionnaire for patients with head and neck cancer

Abstract Purpose The University of Washington Quality of Life Questionnaire (UW-QOL) is an English-language survey used to assess the quality of life of patients with head and neck cancer. The present study aimed to translate this widely used questionnaire into Turkish according to international guidelines and to statistically determine its validity and reliability by administering it to native Turkish-speaking patients. Materials and methods This prospective study was performed at Hacettepe University, Faculty of Medicine, Turkey. The study included patients newly diagnosed as having head and neck cancer. Translation and cultural adaptation of the questionnaire were performed first. Then, the translated version was tested on a consecutive series of patients seen in the department of otorhinolaryngology head and neck surgery and the department of radiation oncology between September 2006 and February 2008. The patients were asked to complete 3 sets of questionnaires. The first set was completed 1 day before the beginning of treatment, the second 3 months after the completion of treatment, and the third 10 days after the second questionnaire was completed. The first and second sets included the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire–Turkish version and UW-QOL–Turkish version. The third set included the Turkish UW-QOL only. Performance status was assessed and rated by a physician using the Karnofsky and ZEW (Zubrod/The Eastern Cooperative Oncology Group (ECOG)/World Health Organization) performance scales, synchronous with the first and second sets of questionnaires. Results The original English version of UW-QOL was carefully translated into Turkish, and a final Turkish version of UW-QOL was developed in an iterative fashion. To determine its validity and reliability, 67 patients were included in the study. Internal consistency (Cronbach α = .757) was adequate, and test-retest reliability (interclass correlation coefficient, 0.941) was excellent. The composite scores of the translated UW-QOL were compared statistically with the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire scores, Karnofsky and ZEW performance scales, T stage of the disease, and UW-QOL global questions scores to support the scale's construct validity, and statistically significant associations were observed. Conclusions The Turkish UW-QOL appears to be a valid and reliable tool for use with Turkish patients with head and neck cancer; it can also be used in clinical investigations and routine clinical practice in Turkey.