Women who survive breast cancer show significant neurologic impairment, with outcomes appearing to be significantly poorer for those treated with chemotherapy, according to a report in the Archives of Neurology.
Investigators at Stanford University School of Medicine in California conducted an observational study to determine whether profiles of brain activation differ among breast cancer survivors treated with or without chemotherapy, compared with healthy control women. The study included 25 women with breast cancer who received chemotherapy, 19 women with breast cancer who did not receive chemotherapy, and 18 healthy female controls, all matched for age and other demographic variables. The women were asked to perform card-sorting tasks, and the researchers used functional MRI to measure activation in several areas of the brain.
Areas of Deficit
The results showed that women who had breast cancer “demonstrated significantly reduced activation in the left middle dorsolateral prefrontal cortex and premotor cortex compared with healthy controls,” the authors reported. “The chemotherapy group also demonstrated significantly reduced left caudal lateral prefrontal cortex activation and increased perseverative errors and reduced processing speed compared with the other two groups,” they added. “Reduced left caudal lateral prefrontal cortex activation was significantly correlated with higher disease severity and elevated subjective executive dysfunction in the chemotherapy-treated women.” The study also found that the effects of chemotherapy on brain function may be exacerbated by such factors as increased age and lower educational level.
Although primary breast cancer has not been associated historically with neurologic problems, “a growing body of evidence suggests that patients are at increased risk for altered brain structure and function,” the authors noted. “This study provides further evidence that primary [breast cancer] may cause measurable brain injury,” they stated in their conclusion. “Women treated with chemotherapy may show additional prefrontal deficits and have difficulty compensating for neurobiological changes such that they also show impaired executive function. The left caudal lateral prefrontal region may be particularly vulnerable to the effects of chemotherapy and/or disease severity and may represent a novel biomarker of subjective or subclinical executive dysfunction in chemotherapy-treated women.” ■
Kesler SR, et al: Arch Neurol 68:1447-1453, 2011.