The FMRI Study On Executive Function Alternations Of Breast Cancer Patients After Chemotherapy

Breast cancer is the most common cancer in women. Most of patients diagnosed of breast cancer are treated with surgery combined with chemotherapy and the application of chemotherapy significantly increase the survival probability. However, with the improvement of treatment, the side-effects of chemotherapy are reported frequently, such as cognition dysfunction and other brain functions impairment.Chemotherapy influences the central nervous system possibly through increasing cell death, oxidative stress and microglia activity, and decreasing the neurotrophic factors. Previous studies show that the breast cancer patients display cognitive impairments after chemotherapy, particularly on the capability of memory, attention, information processing and executive function. The executive function mainly includes planning, execution, problem solving, and cognitive flexibility. Central executive network is responsible for the executive function, which mainly focuses on the frontal lobe and parietal lobe, and connects several neocortical areas that send and receive projections from almost all of the cortical sensory systems, motor systems and numerous subcortical structures to accomplish complex cognition processes. Impairments to central executive network impact patients’working performance and quality of life. In this study, we investigated the executive function alternations of breast cancer patients after chemotherapy using resting-state functional magnetic resonance imaging (rs-MRI) and neuropsychological tests. The functional connectivity of dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC) was calculated from the rs-fMRI data in breast cancer patients (BC group,32) and the control group (HC group,24), respectively. Then the correlations between the connectivity strength of right DLPFC, left PPC and the behavior performance were further analyzed with correlation analysis.The evaluation results of capability of processing various complex cognition events showed that the executive function of the breast cancer patients was impaired after chemotherapy. The functional connectivities of right DLPFC and left PPC in the BC group were significantly altered in comparison with those in the HC group, respectively, which indicated the dysfunction of central executive network. Meanwhile, the executive deficits were found correlated with the functional connectivity of right DLPFC-right IFG (Inferior frontal gyrus) and left PPC-right SFG (Superior frontal gyrus) in the patients, respectively. These findings provided an evidence that the alternation of executive function of breast cancer patients after chemotherapy might correlated with the executive network of the brain and demonstrated the side-effects of chemotherapy.