Pain and Cognition of Breast Cancer Survivors Treated with Chemotherapy: The Mediating Role of Depression

Objectives: While chemotherapy is the primary contributor to cancer-related cognitive impairment (CRCI), interindividual differences in CRCI are not well-understood. Studies suggest that breast cancer (BC) survivors who are in pain are more likely to experience depression, which in turn contributes to CRCI, although this hypothesis is not yet tested. Therefore, this study aimed to investigate the relationship between pain and CRCI among BC survivors and the mediation effect of depression on this relationship. Methods: As a secondary analysis of a descriptive cross-sectional study investigating fatigue and preferred types of fatigue self-management in BC survivors recruited from five tertiary hospitals in South Korea; of the 229 participants, data on 186 who received chemotherapy were analyzed. Study participants were aged between 20 and 69 years, diagnosed with stage I to III, and treated with chemotherapy and/or radiation therapy. Measurement was done with Korean versions of the Cognitive Failure Questionnaire (to assess CRCI), Brief Pain Inventory (for pain severity and interference on daily functioning), and C-ESD (for depression). To assess bivariate relationships between pain, depression, and CRCI, Pearson correlation was used. A mediation analysis was used to examine the effect of depression on CRCI. Results: Significant associations were found among pain, depression, and CRCI (all P < 0.01). Furthermore, a mediation effect of depression was found on the association between pain and CRCI (severity, β = 1.26, SE = 0.38, 95% confidence intervals [0.60, 2.08]; interference, β = 1.53, SE = 0.32, 95% confidence intervals [0.95, 2.20]). Conclusion: Findings indicate that among BC survivors, those with higher pain tend to show higher depression and consequently had lower cognitive function. Implication for Nursing Practice: Oncology nurses may need to identify BC survivors with higher pain, and screening those survivors could be a strategy to identify those at higher risk for CRCI. Also, nurses should focus on managing depression to prevent and/or treat CRCI in BC survivors.