Women with breast cancer who were taking tamoxifen and steroidal aromatase inhibitors had a decreased risk for a neurogenerative disease, specifically Alzheimer's disease and dementia, according to the findings of a retrospective study presented during the 2021 virtual AAN Annual Meeting.
Estrogen-modulating therapies (EMTs) reach and affect the brain, said the lead study author Gregory Branigan, BS, a graduate student researcher at the University of Arizona College of Medicine, who conducted the research. “But less is known about the impact of EMTs on long-term brain health in aging groups."
The researchers reviewed the medical records of 57,843 perimenopausal to postmenopausal women with breast cancer, who were included in the Humana 2007-2017 claims database. The dataset consists of Medicare and private payer claims from across the United States.
The researchers identified patients undergoing EMT for breast cancer. They found that women who had been exposed to EMTs, including tamoxifen and steroidal aromatase inhibitors, had significantly fewer diagnoses of neurodegenerative disease, especially Alzheimer's disease (relative risk 0.827; p<0.0001).
The cognitive side effects of tamoxifen—sometimes referred to as chemo brain—are well-described in cancer patients, noted Ashley Aaroe, MD, a neuro-oncology fellow at MD Anderson Cancer Center in Houston, TX, who was not involved with the study.
“Preclinical work also has shown that estrogen has a variety of effects in the brain, most of them helpful in terms of learning and memory, including enhancing neuroplasticity and modulating neurotransmitter release. Therefore, it's biologically counterintuitive that use of medications that block the production, release, and effects of estrogen in the brain might be protective against neurodegenerative diseases like Alzheimer's dementia," said Dr. Aaroe, who has published work on neurologic complications of cancer and cancer treatment.
“This abstract is an interesting jumping off point for further investigations," said Dr. Aaroe. “I'd want to know if patients with breast cancer on these medications are not being diagnosed with neurodegenerative diseases as frequently for reasons other than the drugs themselves being protective," Dr. Aaroe concluded.
Branigan and Dr. Aaroe had no disclosures.
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AAN Abstract S19.004: Branigan G, Soto M, Rodgers K, Brinton R. Breast cancer therapies reduce risk of Alzheimer's disease and dementia: Clinic to bench translation.
Neurology Today Video: Estrogen-Modulating Therapies Associated with Lower Risk of Dementia in Breast Cancer Patients.