Effects of cancer therapy on hippocampus-related function

Abstract

Cancer treatments such as chemotherapy and radiotherapy are widely used to treat primary and metastatic cancers. Epidemiological studies have demonstrated that these types of treatment can effectively and successfully extend the lifespan of cancer patients, but they are also associated with various neurological complications such as cognitive deficits, seizures, and emotional problems (Taphoorn and Klein, 2004; Yang and Moon, 2013; Son et al., 2015b). In particular, emerging clinical evidence has revealed that there is a higher incidence of cognitive deficits among various types of cancer patients with peripheral tumors, including breast cancer, colorectal cancer, lymphoma, and brain tumors, following cancer therapy compared with healthy control subjects (Taphoorn and Klein, 2004; Dietrich et al., 2008; Pereira Dias et al., 2014). Thus, of the neurological complications, cognitive impairments are considered to be the major side effect because humans have highly developed cognitive abilities, and deficits in this area may ultimately lead to dementia and a diminished quality of life. Several brain regions, including the hippocampus, prefrontal cortex, amygdala, striatum, and several parts of the parietal lobe, are involved in cognitive processing (Pasupathy and Miller, 2005; Yang and Moon, 2013). In particular, the hippocampus is a limbic structure that is essential for working memory, spatial memory, the consolidation of new information into long-term memories, and the acquisition and retrieval of stored memories. As a result, studies investigating cancer treatment-induced cognitive impairments typically assess hippocampal dysfunction. Thus, the present article reviews the possible mechanisms underlying hippocampus-related cognitive impairments following chemotherapy and radiotherapy.