Cognitive changes identified in patients undergoing chemotherapy are common and referred to as “chemo brain.” Patients report fuzzy thinking and inability to think straight. The assumption has been that chemotherapy causes these cognitive changes, but a new study presented at SABCS suggests that cognitive changes are present in breast cancer patients prior to undergoing chemotherapy and appear to be related to fatigue and anxiety.
Cognitive problems in patients with breast cancer remain unexplained, and there are no treatments. In 26 studies, 69% of patients showed some evidence of cognitive decline, said lead author Bernadine Cimprich, PhD, RN, professor emeritus at the University of Michigan School of Nursing in Ann Arbor. “We believe that ‘chemo brain’ may not be an appropriate label for cancer-related cognitive problems. Our study found that pretreatment altered neural activation and fatigue contributed to cognitive problems in women diagnosed with breast cancer before they were treated,” Cimprich stated.
The study enrolled 65 women with stages 0 through IIa breast cancer and 32 healthy age-matched controls. Among those with breast cancer, 28 were scheduled for adjuvant chemotherapy and 37 for radiation alone as adjuvant therapy.
Functional magnetic resonance imaging (fMRI) was utilized to assess changes in the brain while performing tasks associated with working memory before adjuvant treatment and 1 month after adjuvant therapy. In the adjuvant chemotherapy group, fMRI scans were done after surgery, 1 month before adjuvant chemotherapy, and 1 month after chemotherapy. In the radiation-alone group, scans were done after surgery, 1 month before starting radiation, and then 5 months later, roughly similar to the chemotherapy patients. Healthy controls had fMRI scans performed after a negative mammogram and again 5 months later.
All participants provided self-reports of cognitive function and fatigue at the same time points, Cimprich said.
The researchers focused on the left inferior frontal gyrus, a region involved in working memory tasks. The chemotherapy group reported significantly greater fatigue levels than did the other 2 groups and performed less well on the verbal memory tasks before treatment, which corresponded to reduced activity in the left inferior frontal gyrus on fMRI. Healthy controls had more activation in the brain region of interest than women in the other 2 groups, while patients slated for radiation were found to have levels of brain activity on fMRI in between those of the other 2 groups.
Regardless of which group patients were in, fatigue level was correlated with performance on the memory task.
At the second time point, few differences in brain fMRI were observed between groups, largely explained by the fact that the chemotherapy patients had recovered much of the ability to perform working memory tasks.
According to Kent Osborne, MD, Baylor College of Medicine, Houston, Texas, and moderator of the press conference at which these findings were discussed, Cimprich’s study makes sense because he has observed that the worry and stress of a breast cancer diagnosis, as well as the anticipatory anxiety before chemotherapy, can affect cognitive function.
“These findings underscore the need for increased awareness among clinicians that cognitive problems can begin before treatment in women with breast cancer and the problems are related to fatigue. Early identification of women at greater risk is important, because cognitive problems can worsen over time,” Cimprich stated.
To sign up for our newsletter or print publications, please enter your contact information below.
