A new study shows that some women with breast cancer who have been treated with chemotherapy experience a decrease in mental function and a change in brain activity while multitasking.
The research explains the phenomenon called "chemo brain" which affects most patients who have undergone chemotherapy. It describes the reported changes in memory and thinking, especially when multitasking.
"Cognitive complaints of people increase with chemotherapy and we are trying to find out why," said lead researcher Sabine Deprez. "Difficulty in multitasking is one of the biggest complaints." It has been hard to distinguish between decreased mental performance associated with chemotherapy and those changes due to the advanced stage of the disease. Studies have always focused on comparing chemotherapy patients and healthy people.
The new study by Deprez and her team compared the mental performance of 18 women before chemotherapy treatments for breast cancer and a couple of months after that. The subjects were also compared with female patients with breast cancer but not receiving chemotherapy, and with women without any treatment or cancer. Other studies used imaging to differentiate brain activity between healthy people and cancer patients who received chemotherapy.
The researchers from University Hospital Gasthuisberg of the Catholic University of Leuven in Belgium used functional MRI (magnetic resonance imaging) to compare the women before and after chemotherapy. The 18 women with breast cancer who received chemotherapy were compared with 16 women with breast cancer who did not receive chemo and 17 healthy women with no breast cancer. The women were tested one or two weeks before chemotherapy and four to six months after it. The other groups were tested at the same times.
"The special thing about how we did the design was that before we did it we adjusted the difficulty for each patient, and the performance of everyone was between 70 percent and 80 percent," Deprez said. It allowed the team to measure brain activity changes during the task and not the ability to complete it.
The two groups did not show any change in terms of brain activity, while the group that underwent chemotherapy showed significantly decreased brain activation. The chemo group also complained about "foggy thinking" more than women from the two other groups.
By understanding which patients are more at risk of decreased brain activation, the researchers hope to encourage personalized medical treatments to minimize the risks while still effectively treating cancer. The cognitive effects of treatment are as important as other treatment-related side effects.