Unravelling the Mechanisms of Cancer-Related Cognitive Dysfunction in Non-Central Nervous System Cancer

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

Background

Cancer-related cognitive impairment is a common and potentially debilitating symptom experienced by patients with non-central nervous system (CNS) cancers, 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 for the Portuguese population. Therefore, the purpose of this study was to evaluate the psychometric properties of the FACT-Cog-v3 among patients with non-CNS cancers in Portugal.

Methods

The validation study was conducted based on a convenience sample of 281 patients with non-CNS cancers, 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. Acceptable discriminant validity, with weak and moderate correlations, was demonstrated 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 patients with non-CNS cancers, with relevance for research and clinical practice.

Neuro-Oncology Patients as Human Research Subjects: Ethical Considerations for Cognitive and Behavioral Testing for Research Purposes

Simple Summary

Previous publications have elaborated on the exposure of ethical issues surrounding the enrollment and neurological testing of brain cancer patients into clinical studies. Existing literature has been tailored to provide insight on how to overcome ethical challenges for clinical team members but not for the research component that runs in parallel. The aim of this paper is to highlight the obstacles that researchers encounter when obtaining informed consent and administering language, cognitive or behavioral tasks for the sole purpose of research. Researchers should be encouraged to practice their best judgment and effectively communicate the purpose of the study while emphasizing the voluntary participation of neurologically impaired cancer patients. The solutions proposed in this paper can serve as future reference and a guide on maintaining a transparent balance between research and clinical testing for both researchers and clinical team members in the neuro-oncology field.

Abstract

Language, cognition, and behavioral testing have become a fundamental component of standard clinical care for brain cancer patients. Many existing publications have identified and addressed potential ethical issues that are present in the biomedical setting mostly centering around the enrollment of vulnerable populations for therapeutic clinical trials. Well-established guides and publications have served as useful tools for clinicians; however, little has been published for researchers who share the same stage but administer tests and collect valuable data solely for non-therapeutic investigational purposes derived from voluntary patient participation. Obtaining informed consent and administering language, cognition, and behavioral tasks for the sole purpose of research involving cancer patients that exhibit motor speech difficulties and cognitive impairments has its own hardships. Researchers may encounter patients who experience emotional responses during tasks that challenge their existing impairments. Patients may have difficulty differentiating between clinical testing and research testing due to similarity of task design and their physician’s dual role as a principal investigator in the study. It is important for researchers to practice the proposed methods emphasized in this article to maintain the overall well-being of patients while simultaneously fulfilling the purpose of the study in a research setting.