Study Finds Changes in Brain Activity in Breast Cancer Patients Receiving Chemotherapy


Key Points

  • After receiving chemotherapy, patients with breast cancer had a significant increase in cognitive complaints and a significant decrease in brain activity in components of their multitasking network.
  • The changes may be related to chemotherapy-induced damage or reduced connectivity between brain regions rather than to changes in effort or functional strategy.

A small study of 18 patients with breast cancer treated with chemotherapy has found a significant increase in cognitive complaints and significant correlations between these increases and decreases in multitasking-related brain activation. The study by Deprez et al is published in the Journal of Clinical Oncology.

Study Method

The study involved three cohorts: 18 patients with breast cancer scheduled to receive chemotherapy, 16 patients not scheduled to receive chemotherapy, and 17 matched healthy control subjects. All performed a functional magnetic resonance imaging (MRI) multitasking task in the MRI scanner at baseline (before start of treatment in the chemotherapy group) and at 10 to 12 months later (4 to 6 months after finishing treatment in the chemotherapy group).

The task difficulty level was individually adjusted to match performance across participants. The testing consisted of cross-modal single visual and auditory tasks, a dual task combining both single tasks simultaneously, and a multitasking test combining the dual task with a short-term visual memory task. Statistical Parametric Mapping 8 software was used for within-group, between-group, and group-by-time interaction image analyses.

Study Findings

There were no significant differences among groups in age, verbal intelligence quotient, depression score, anxiety score, or cognitive failure questionnaire (CFQ) total score at baseline. The chemotherapy group had a significant increase in cognitive complaints on the CFQ at follow-up testing (P < .05), whereas no changes were observed in the control groups.

No significant differences in difficulty levels were observed between groups and test time points, and performance accuracy and reaction times did not differ between groups. Significantly better performance and faster reaction times were observed at follow-up testing in all groups, with no group-by-time interaction being identified.

Voxel-based analysis of variance with and without depression score as a covariate showed no significant differences in multitasking-specific brain activation among the three groups at baseline. Voxel-based paired t tests showed no significant changes in brain activation from baseline for the single visual or auditory tasks in any of the groups. However, brain activity decreased significantly (P < .05) compared with baseline in the chemotherapy group during multitasking in two components of the multitasking network—the left anterior cingulated gyrus and the left intraparietal sulcus.

No reduction in activation within this multitasking network was observed in the control groups. No significant increases in brain activity from baseline within or outside the multitasking network were observed in any of the groups. A significant group-by-time interaction (P < .05) was identified, reflecting decreased activation in the left anterior cingulate cortex in the chemotherapy group and not in healthy controls.

These results suggest that changes in brain activity may underlie chemotherapy-induced cognitive complaints,” concluded the study authors. “The observed changes might be related to chemotherapy-induced damage to the brain or reduced connectivity between brain regions rather than to changes in effort or changes in functional strategy. To the best of our knowledge, this is the first longitudinal study providing evidence for a relationship between longitudinal changes in cognitive complaints and changes in brain activation after chemotherapy.”

The corresponding author of the study is Sabine Deprez, PhD, Department of Radiology, University Hospital Gasthuisberg, Katholieke Universiteit Leuven, Belgium.

The study was supported by grants from Research Foundation Flanders and Stichting tegen Kanker.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.