Validation study of the Functional Assessment of Cancer Therapy - Cognitive Function – Version 3 for the Portuguese population

Abstract

Abstract Background: Cancer-related cognitive impairment is a common and potentially debilitating symptom experienced by non-central nervous system (CNS) cancer patients, with negative impact on their quality of life. The Functional Assessment of Cancer Therapy-Cognitive Function–Version 3 (FACT-Cog-v3) is the most extensively used instrument specifically developed to evaluate cognitive complaints in adult cancer patients. Nevertheless, this self-report measure is not yet validated to the Portuguese population. Therefore, the purpose of this study was to evaluate the psychometric properties of the FACT-Cog-v3 among non-CNS cancer patients in Portugal. Methods: The validation study was conducted based on a convenience sample of 281 non-CNS cancer patients, aged between 18 and 65 years, recruited online. A confirmatory factor analysis (CFA) was used to test the factor structure of the Portuguese FACT-Cog-v3 version; internal consistency analysis was also conducted. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core-30 (EORTC QLQ-C30–version 3) and the Hospital Anxiety and Depression Scale (HADS) were also used to test the concurrent, convergent, and discriminant validity of the scale. Results: CFA supported a four-factor model with good fix indexes and internal consistencies: perceived cognitive impairments (α=0.97), comments from others (α=0.92), perceived cognitive abilities (α=0.93), and impact on quality of life (α=0.92). Concurrent, convergent, and discriminant validities were confirmed. Moderate and strong correlations were found between the FACT-Cog-v3 subscales and the QLQ-C30 cognitive functioning subscale. Good convergent validity, with moderate correlations, was found between the FACT-Cog-v3 subscales and the HADS-A, HADS-D, and QLQ-C30 fatigue, sleep disturbance, and global health status subscales. There was acceptable discriminant validity, with weak and moderate correlations, between the FACT-Cog-v3 subscales and the QLQ-C30 pain and nausea/vomiting subscales. Conclusions: The Portuguese FACT-Cog-v3 version can be considered a reliable and valid measure to assess cognitive concerns of non-CNS cancer patients, with relevance for research and clinical practice.