Breast cancer affected by hormones is often treated with hormone-modulating therapy (HMT) which has been the subject of conflicting research findings regarding its impact on the risk of developing Alzheimer’s disease and other types of dementia. However, a new study published in the journal JAMA Network Open suggests that HMT is associated with a 7% lower risk of developing Alzheimer’s disease and related dementias later in life. This study, led by Francesmary Modugno, PhD, MPH, observed almost 19,000 women aged 65 and older who had been diagnosed with breast cancer between 2007 and 2009 and found that those who received HMT had a lower risk of dementia compared to those who did not.
Between 70-80% of new breast cancer diagnoses are hormone receptor-positive, meaning their tumor cells have proteins that bind to estrogen, progesterone, or both. These types of breast cancer are often treated with HMT before or after surgery. There are three main types of HMT: those that block estrogen from linking to cancer cells, those that bind to receptors on the tumor and break them down, and those that lower or stop estrogen production in the body. While some research has suggested that HMT may have adverse effects on cognition, the recent study found a protective effect against Alzheimer’s disease and related dementias.
The study found that women aged 65 and older with breast cancer who received HMT had a 7% risk reduction in developing Alzheimer’s disease and related dementias overall. However, there were variations in the protective effects of HMT based on age and race. It was observed that the protective effect of HMT was most pronounced in women aged 65 to 69, with the effect diminishing as participants aged, especially over 80 years old. Additionally, racial differences were noted, with Black women experiencing a greater reduction in risk compared to white women. These findings highlight the importance of considering individual factors such as age and race when determining treatment plans.
Verna Porter, MD, a neurologist and director of Dementia, Alzheimer’s Disease, and Neurocognitive Disorders at Pacific Neuroscience Institute, expressed cautious optimism about the study results. While the findings show promise, it is essential to develop personalized treatment plans that take into account individual patient factors to optimize benefits and minimize risks. With the prevalence of Alzheimer’s and related dementias expected to rise with an aging population, finding effective prevention strategies is crucial for improving public health outcomes. Continued research into the mechanisms behind the observed racial disparities and the specific effects of different types of HMT on dementia risk is necessary for developing targeted interventions.
Wael Harb, MD, a hematologist and medical oncologist, emphasized the need for further research to better understand the association between HMT and dementia risk. While the study suggests a potential link, additional investigations are needed to determine the underlying mechanisms and any potential confounding factors. Harb highlighted the importance of considering factors such as the type of HMT used and the impact of chemotherapy on cognitive function. Further studies may help clarify the relationship between HMT and dementia risk and inform the development of personalized treatment guidelines for patients with hormone receptor-positive breast cancer.
