Impact of health,treatment and psychological factors on cognitive functioning after chemotherapy for early breast cancer

The aim of the current study was to review the extent that physical health, treatment and psychological factors contribute to cognitive dysfunction after chemotherapy for breast cancer. PubMed, Medline and PsychINFO searches of the literature published from 1995 to 2008 pertaining to chemotherapy for breast cancer and cognitive dysfunction were reviewed. There is currently insufficient evidence available to evaluate the effect of indirect factors (health, treatment and psychological) on cognitive functioning after chemotherapy. Fatigue and changes in endocrine function are the most frequently investigated factors, although conclusions are limited due to methodological shortcomings. The impact of other health and treatment factors has been inadequately addressed, with many variables examined in only one of the 22 reviewed studies. Importantly, although depression and anxiety can significantly influence neuropsychological test performance, mood has been inconsistently measured and analysed in regards to cognitive performance in this literature. In addition, indirect factors may affect cognitive domains differently, requiring further investigation of specific domains after chemotherapy. Because chemotherapy can negatively affect numerous organ systems and as yet no systematic investigations of health, treatment or psychological factors have been conducted, the authors conclude that it is currently premature to attribute all cognitive change after chemotherapy treatment to cytotoxic drugs.