Chemobrain: a systematic review of structural and functional neuroimaging studies

Nowadays, chemotherapy-induced cognitive impairment or 'chemobrain' is a well-established clinical syndrome, consisting of moderate to subtle cognitive changes across various domains, especially working memory, executive function and episodic verbal memory that persist only in a subgroup of long-term cancer survivors. In recent years, several studies using neuroimaging techniques have reported structural and functional neural changes associated with chemotherapy. This review provides an overview of the relevant advances that neuroimaging techniques have added to the understanding of the underlying mechanisms of chemotherapy-induced cognitive impairment. In summary, our review showed: (i) a pre-treatment (prior to chemotherapy) widespread decrease in white matter (WM) volume as well as an increased level of activation of the frontoparietal attentional network of cancer patients compared to controls; (ii) an early diffuse decrease of gray matter (GM) and WM volume together with a decrease of the overactivation in frontal regions in chemotherapy-treated patients compared to controls and (iii) a long-term persisting decrease in GM and WM volumes together with a predominantly frontal cortex hypoactivation in only a subgroup of chemotherapy-treated patients.