Cross-cultural adaptation, reliability, and validity of the Turkish version of the Cancer Fatigue Scale in patients with breast cancer

Abstract

Background/aim: The Cancer Fatigue Scale (CFS) was developed to evaluate the severity of fatigue in patients with breast cancer. Theaim of this study is to translate and culturally adapt a Turkish version and investigate the validity and reliability of the CFS in Turkishpatients with fatigue symptoms.Materials and methods: Eighty participants completed the Turkish version of the CFS for breast cancer and the European Organizationfor Research and Treatment of Cancer Quality of Life Core Questionnaire “Core 30” (EORTC QLQ-C30). Test–retest reliability wasevaluated by repeating the CFS with a 7-day interval.Results: The CFS demonstrated high test–retest reliability (ICC = 0.95) and good internal consistency (Cronbach’s alpha = 0.74) for alldomains. The Kaiser–Meyer–Olkin measure of sampling adequacy was found to be 0.819, which is considered to be satisfactory (>0.5).Correlations between domains of CFS physical and EORTC physical (r: 0.77), CFS cognitive and EORTC cognitive (r: 0.70), and CFSphysical and EORTC fatigue (r: 0.80) were found to be significant.Conclusion: The Turkish version of the CFS is a reliable and valid instrument to assess physical, effective, and cognitive dimensions offatigue. The CFS may be used to evaluate the severity of fatigue in Turkish-speaking breast cancer patients.