A decline in cognition ("brain fog") among women who receive chemotherapy as part of breast cancer treatment may be due to external stressors and not the chemotherapy itself.
Chemotherapy and Post-traumatic Stress in the Causation of Cognitive Dysfunction in Breast Cancer Patients
Authors: Hermelink, K. et. al.
Source: J Natl Cancer Inst (2017) 109(10): djx057
Cognitive dysfunction (also called "brain fog" and "chemo-brain") is experienced by many individuals with different types of cancer, including breast cancer. It has long been suspected that this dysfunction is at least in part due to chemotherapy. However, studies have not consistently shown that chemotherapy actually has this effect. There are many factors that affect cognition, such as anxiety, sick leave, sleep disturbance and physical illness. Such factors have not been closely investigated to learn about their impact upon mental functioning among cancer patients.
This group evaluated over 220 women, over half of which had diagnoses of breast cancer. They were placed into three groups: breast cancer with chemotherapy, breast cancer without chemotherapy and no breast cancer diagnosis. The groups were evaluated at three time points during the observation period. Written and computerized tests were conducted to evaluate intelligence and cognition. Participants were also evaluated for symptoms of posttraumatic stress disorder (PTSD).
There were no differences in cognition among groups. However, by the last time point (7-12 months after the first time point), all groups experienced a slight decline in cognitive performance. Women receiving chemotherapy did not demonstrate more impairment than other women. But, PTSD symptoms did have a significant effect upon some of the measures of their cognition. This was the case for the women who did have chemotherapy, as well as those who did not.
The investigators determined that chemotherapy did not play a role in the cognitive impairment of breast cancer patients. However, the presence of PTSD did. The psychological impacts of diagnosis and treatment, as well as the stress that they can impose on patients' lives, help to explain the impaired thought processes that many breast cancer patients experience. Providers should engage with patients about their anxieties and difficulties, and patients should be encouraged to talk about their stressors and coping needs.