Functional Assessment of Cancer Therapy-Cognitive Scale (FACT-Cog)

The third version of the FACT-Cog (Wagner et al., 2009) is a 37-item questionnaire, using a 5-point Likert-scale, with a total score ranging from 0 to 148. It consists of four subscales: perceived cognitive impairments (PCI, 20 items), comments from others (4 items), perceived cognitive ability (PCA, 9 items), and impact on quality of life (QoL, 4 items). This questionnaire is designed to measure cognitive complaints and abilities in the past 7 days. Higher scores in all subscales indicate better cognitive function and quality of life. This highly reliable questionnaire has been widely used in previous breast cancer studies (Von Ah and Tallman, 2015; Janelsins et al., 2017; Vardy et al., 2019). A Farsi version of this questionnaire with excellent internal consistency was used in this study (α = 0.97).