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Chemotherapy Changes Brain Activity, Based on MRI

May 27, 2014

        Key Points: 
  • One of the most common cognitive complaints after chemotherapy is difficulty with multitasking.

  • Brain activity in the patients receiving chemotherapy was measured (through functional MRI) one to two weeks prior to treatment, and then four to six months after finishing treatment; the control groups were evaluated at matched time intervals.

  • Data showed significant decreases in brain activity during multitasking after chemotherapy in patients with breast cancer. However, this decrease was not seen in healthy women or women with breast cancer not receiving chemotherapy.

  • Increases in cognitive complaints after chemotherapy correlated significantly with decreases in brain activity during multitasking.


By Shira Klapper, Senior Writer/Editor

A new study in the Journal of Clinical Oncology (JCO) found that patients with breast cancer who had received chemotherapy showed significant alterations in brain activation from the time they started treatment until 12 months after their first dose. The study, “Longitudinal Assessment of Chemotherapy-induced Alterations in Brain Activation during Multitasking and Its Relation with Cognitive Complaints,” is the first of its kind to look at patients’ cognitive complaints and changes in specific areas of the brain related to multitasking following chemotherapy. The article was published in in the JCO online, May 27, ahead of print.

First author, Sabine Deprez, PhD, stated that the decision to look at multitasking, and at younger people in particular, was motivated by what doctors saw and heard from patients in clinic.

“Patients we see in the clinic often complain about cognitive problems,” said Ms. Deprez. “And one of the biggest complaints, especially among younger, highly educated people who have high-demanding jobs is that they have difficulty with tasks requiring them to coordinate and deal with different issues at the same time. Based on this complaint, we made the decision in this study to look, not at memory, but at multitasking.”

The research group, based out of University Hospital Leuven, in Belgium, designed the study to include three groups of women: 18 with breast cancer receiving chemotherapy, 16 with breast cancer who were not receiving chemotherapy, and 17 healthy people. All of the women were asked to perform multitasking activities while in an MRI at two time points: At one to two weeks before the patients in the chemotherapy group received treatment and four to six months after treatment.

The inclusion of women with breast cancer who were not receiving chemotherapy allowed the study to avoid a tricky methodological issue: if women receiving chemotherapy were compared only to people who were cancer-free, it would be possible to conclude that any changes seen in brain activation were due to the disease itself and not to treatment.

In addition, to account for inter-group differences in mental health that might have affected outcomes, all of the women completed an assessment to measure depression and anxiety.

The findings? At the beginning of treatment, brain activity in areas of the brain known to “light up” during multitasking activities were not different between the three groups. However, at the four- to six-month point, women who had received chemotherapy showed significantly decreased brain activity while completing the multitask exercise.

An interesting finding

While women who had received chemotherapy reported more cognitive complaints and had MRI’s showing decreased brain activity, they did not actually perform any worse on the tasks than women from the other groups.

Commenting on this interesting finding, Ms. Deprez theorized that it might be due to chemo-induced structural changes in the brain.

“Other studies that looked specifically at structural changes to the brain found decreases in grey matter volume and changes in the white matter microstructure, which affects the connections between the frontal and parietal parts of the brain,” said Ms. Deprez.” And this could make a task feel like it required more effort. You can still do the task, but it feels subjectively more difficult and frustrating.”

A new way of thinking about cognitive complaints

According to Ms. Deprez, this study might help turn the tide in the way doctors view cognitive complaints, especially in non-U.S. countries, where awareness of chemo-induced cognitive changes is not as strong.

“The study will hopefully inspire researchers to start developing ways to ameliorate the problem, for example, with cognitive training.”




Sabine Deprez PhD, is a researcher at KU Leuven University, Belgium, in the Department of Imaging and Pathology and the Department of Radiology.





Click here to read the abstract.


Click here to read the PDF.


Deprez, S, Vandenbulcke, M, Peeters, R, et al. Longitudinal assessment of chemotherapy-induced alterations in brain activation during multitasking and its relation with cognitive complaints. J Clin Oncol. 2014; Published online ahead of print 5.27.2014

The Exclusive Coverage series on ASCO.org highlights selected research from JCO with additional perspective provided by the lead or corresponding author.

@ 2014 American Society of Clinical Oncology

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