Late effects of adjuvant chemotherapy for adult onset non-CNS cancer; cognitive impairment, brain structure and risk of dementia.

Few studies have investigated the late (i.e. ≥ 5 years post-treatment) effects of chemotherapy for non-central nervous system (non-CNS) cancer on the brain. Here we discuss the studies that have investigated the late effects of adjuvant chemotherapy for non-CNS cancer on cognitive function (n=6); brain structure and function (n=5); and incidence of dementia (n=4). The neuropsychological studies showed long-term adverse cognitive problems in chemotherapy-exposed breast cancer survivors. This is in line with results from neuroimaging studies that report long-term brain structural alterations after chemotherapy. The studies exploring the association between chemotherapy and the incidence of dementia were contradictive and showed no clear relationship between the two phenomena. Although several methodological issues limit the validity and interpretation of some of the results of these studies, they suggest that chemotherapy is associated with subtle, yet long-lasting cognitive deficits, possibly related to brain structural and functional differences, but as yet not with an increased risk of dementia.