The role of oxytocin in mediating the relationships between social factors and chemotherapy-associated cognitive decline in female patients with breast cancer.

While chemotherapy can cause debilitating side effects, social support, particularly that of an intimate partner, can be protective. This study examined the relationships between couple satisfaction and chemotherapy-associated subjective and objective cognitive decline in a cohort of breast cancer patients, in addition to the roles of other social factors. Because of oxytocin's role in social bonding and cognition, circulating oxytocin and oxytocin receptor gene expression in peripheral blood mononuclear cells were investigated as potential mediators. Partnered breast cancer patients (n = 48) completed cognitive assessments and provided blood samples at 3 timepoints: pre-chemotherapy, during chemotherapy, and post-chemotherapy. Participants completed a retrospective couple satisfaction questionnaire, provided information about partner duration as well as other social factors (e.g., number of people in the household, number of dependents under 18), and completed a retrospective perceived general social support questionnaire. Analyses were completed using linear mixed effects and regression models. More satisfaction in an intimate relationship related to both less subjective and objective cognitive decline over chemotherapy. Similarly, higher perceived social support related to less overall objective cognitive decline over chemotherapy, though this relationship was less robust than that observed with high couple satisfaction. Remarkably, circulating oxytocin decreased over chemotherapy but was only associated with partner duration and not with cognitive measures. This study suggests a potential benefit of social-directed interventions for the treatment of cognitive side effects of chemotherapy, either from an intimate partner or more generally. Furthermore, understanding biological mechanisms is important to develop novel preventative and interventional therapies to mitigate the adverse side effects of chemotherapy.