Chemotherapy and Cognitive Function in Breast Cancer Patients: The So-Called Chemo Brain

Self-perceived problems of cognitive functioning after treatment for early-stage breast cancer have the potential to substantially affect the lives of patients. In the past two decades, neuropsychological studies have accumulated evidence of corresponding cognitive deficits that have mostly been attributed to neurotoxic effects of chemotherapy. Nevertheless, observations of impaired cognitive functioning already before the start of adjuvant or neoadjuvant chemotherapy question the singular role of chemotherapy for the causation of these deficits. The divergence between mostly subtle neuropsychological deficits and often dramatic subjective cognitive complaints as well as the lack of association between both in the majority of studies present an unsolved puzzle. Recent investigations that include brain imaging have begun to yield tentative answers in this regard. The present review aims at briefly summarizing and integrating the current evidence from clinical studies for purposes of patient counseling.