Breast cancer appears to cause brain injuries

Breast cancer is the most common cancer in Australian women, and it causes brain injuries. AAP/Julian Smith.

Breast cancer appears to cause “measurable brain injury” even if women do not undergo chemotherapy, and the disease can mentally impair survivors, new research has found.

“These impairments significantly extend disease-related disability, affecting home, educational, and occupational activities,” the authors write in the study, published today in Archives of Neurology.

Researchers from Stanford’s medical divisions in California compared three groups of women: 25 breast cancer patients who had received chemotherapy, 19 breast cancer patients who had not received chemotherapy, and 18 healthy women. The women were assigned memory and pattern-recognition tasks, verbal fluency tests, given MRI scans, and screened for psychiatric symptoms. Just over half of the breast cancer patients were taking Tamoxifen, an oestrogen receptor blocker, that is known to cause mental impairments in many women.

Previous studies have found brain and behavioural impairment in women undergoing chemotherapy, the authors report, but this was the first they knew of that showed such damage also occurred without chemotherapy.

The study, Prefrontal Cortex and Executive Function Impairments in Primary Breast Cancer, found that “female survivors of breast cancer demonstrated significantly reduced [brain] activation, irrespective of treatment history.” However, the women who were treated with chemotherapy showed a “significantly poorer outcome”, suffering more extensive brain injury and “impaired executive function”.

Among patients being treated with chemotherapy, women who were older or less educated suffered relatively more impairment, indicating to researchers that they had less “cognitive reserve” to be called on as the disease and treatment took their toll.

John Boyages, Professor of Breast Oncology and Director of the Macquarie University Cancer Institute, said that it was a good study and worth repeating in a larger cohort of patients with more measurements taken.

He also suggested that the situation cancer patients find themselves in would rattle many people’s cognitive abilities. “Finding that brain function is not normal in women who do not have chemotherapy is not surprising. I tell my patients that after a diagnosis of breast cancer, you tend to be in a ‘war-zone’. Sleep is affected, the patients is stressed and very fearful of disease recurrence, hormone levels are affected by treatments and so on,” Professor Boyages said.

Impairment from chemotherapy was common, he said, and patients were warned about the usually temporary effects of “chemotherapy brain”. “Chemotherapy-related memory dysfunction tends to manifest as problems with concentration, ability to focus, organization, and working with numbers. Many women feel forgetful and may struggle remembering people’s names, remembering to do things, or learning new information”.

Breast cancer is the most common cancer suffered by Australian women, with one in 9 women expected to develop it before the age of 85.

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