Chemotherapy effects on brain may be a myth
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“Chemofog” - impairments in memory and in thinking, or “cognition,” that have been attributed to chemotherapy—was not seen in two studies of women being treated for breast cancer, according to a presentation at the 60th annual meeting of the American Academy of Neurology in Chicago..
In Melbourne, Australia, Dr. David G. Darby of CogState Ltd, where a cognitive assessment test bearing its name was developed, and colleagues, used the test to evaluate the changes in cognitive function in breast cancer patients. CogState Ltd. is an international, publicly held company that sells diagnostic tools.
The researchers tested 30 women with breast cancer, and 30 “control” subjects matched by age, before each cycle of chemotherapy and 28 days after the last cycle. Both groups of women also provided a subjective assessment of their cognitive function and feelings of depression and anxiety at each evaluation.
Before chemotherapy was even initiated, cognitive performance and learning ability on the CogState assessment were significantly impaired among patients compared with controls, Darby reported. After the final cycle of chemotherapy, patient performance using the CogState assessment had declined only on speed of identification of objects.
Three women developed cognitive impairment over the course of chemotherapy. However, the results of the objective assessment did not match the women’s subjective reports of depression, anxiety or cognitive performance.
“Prior to chemotherapy, women with breast cancer show subtle but reliable impairment in attention and learning,” Darby’s team concluded. “Chemotherapy-related cognitive impairment was infrequent and did not correlate with subjective cognitive impairment.”
Meanwhile, Dr. Michael J. Boivin of Michigan State University in East Lansing and colleagues presented similar findings for 17 women newly diagnosed with breast cancer prior to chemotherapy or radiation, 21 women with recent benign diagnoses and 20 women who had completed chemotherapy for breast cancer at least one year previously. These women also completed the CogState battery as well as a quality-of-life questionnaire.
Newly diagnosed women with breast cancer were significantly less accurate on memory tests than the one-year survivors and performed “marginally” poorer than women who had received a benign diagnosis.
“These results suggest that cognitive difficulties experienced by women with a new breast cancer diagnosis may be related to stress as a result of the diagnosis and other quality-of-life factors, and not simply due to the effects of chemotherapy or radiation,” Boivin told meeting attendees.
By Martha Kerr
NEW YORK (Reuters Health)
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