Prevalence and Severity of Cognitive Impairment in Korean Cancer Patients as Compared to Healthy Subjects

Saturday, 27 July 2019

Hee-Ju Kim, PhD, RN
college of nursing, Catholic University of Korea, Seoul, seoul, Korea, Republic of (South)

Background: The impact of cancer and its treatment on cognitive impairment has become a focus of oncology research and clinical practice (Wefel et al., 2015). However, the relative significance of cognitive impairment in cancer patients as compared to healthy subjects is unclear in the current literature (Lai et al., 2014). In order to clarify the clinical significance of cognitive impairments in cancer patients and to better understand its mechanisms, it is important to examine factors determining the prevalence and severity of subjective cognitive impairment in cancer patients, as compared to non-cancer healthy subjects (Ahles & Hurria , 2018).

Purpose: This study examined (a) whether cancer patients in two cohorts (patients awaiting for their first chemotherapy; patients undergoing chemotherapy) self-report greater cognitive impairment, both in prevalence and severity, compared to a cohort of actively-employed non-cancer controls; and (b) if any differences in self-reported cognitive impairment are associated with demographic and selected psycho-neurological factors (fatigue, stress, and sleep disturbance).

Methods: Data for two cancer patient cohorts (60 in the pre-chemotherapy cohort and 81 in the active-chemotherapy cohort) were collected from a conveniently selected University Hospital in South Korea, from July 2012 to January 2014. The data for non-cancer healthy controls (n=116) were collected in October 2016 from a conveniently selected community setting. Analysis of variance and chi-square tests were performed to examine the differences of three cohorts in cognitive impairment, demographic and psycho-neurological factors. Hierarchical regressions (both linear and logistic) were performed to predict the cognitive impairment measured in the Functional Assessment of Cancer Therapy–Cognitive Function (Wagner et al., 2009).

Results: Compared to the non-cancer control, both patient cohorts experienced cognitive impairment significantly more severely and more prevalently (18 % in healthy subject cohort vs. 40.7%, 55% in cancer patient cohorts, p < .001). After controlling for the effects of the selected psycho-neurological factors, however, cancer patient cohorts did not statistically differed in the prevalence or in the severity of cognitive impairment from the healthy non-cancer control (all ps >.05). Age, fatigue, and stress were the main factors that accounted for the prevalence as well as the severity of cognitive impairment.

Conclusion: The association with subjective cognitive impairments with psycho-neurological factors has been reported in many previous reports with cancer patients (Chen et al., 2012; Gehring et al., 2015; Myers et al., 2015). Further, the present study found that the psycho-neurological factors may play a pivotal role in experiencing subjective cognitive impairments in cancer patients as well as in general population. Unhealthy psycho-neurological status that is associated with cancer diagnosis and its treatment impairs cognitive function and managing such psycho-neurological status is the key to improve the cognitive function in cancer patients.