Breast cancer affected by hormones is often treated with hormone-modulating therapy (HMT) before or after surgery. There are three main types of HMT — one that blocks estrogen from linking to cancer cells, one that binds itself to the receptors on the tumor and breaks them down, and one that lowers or stops estrogen production in the body. Over the years, there have been conflicting research findings on HMT. Some studies have found that it lowers a woman’s risk of developing Alzheimer’s disease and other types of dementia, while others have found adverse effects on cognition. A recently published study in JAMA Network Open reports that HMT is associated with a 7% lower risk of developing Alzheimer’s disease and related dementias later in life.
For this study, researchers used a federal database from the National Cancer Institute to identify almost 19,000 women ages 65 and older who had been diagnosed with breast cancer between 2007 and 2009. All selected participants did not have a previous diagnosis of Alzheimer’s disease and related dementias, as well as had not used HMT before their breast cancer diagnosis. During an average follow-up period of 12 years, researchers found that 24% of participants given HMT and 28% of non-HMT receiving participants developed Alzheimer’s disease and related dementias. In general, women aged 65 years and older with breast cancer who received HMT had a 7% risk reduction in developing Alzheimer’s disease and related dementias overall. Additionally, researchers also found differences when looking at age ranges and ethnic groups.
Scientists discovered that the dementia-protective effect of HMT was most pronounced in study participants between the ages of 65 and 69. The safeguarding effect diminished as participants aged, especially over the age of 80, where there was an increased risk of Alzheimer’s disease and related dementias in those receiving HMT. Differences were also found in racial groups, with Black women ages 65 to 74 receiving HMT having a 24% reduction in their risk of developing Alzheimer’s disease and related dementias, compared to 11% in white women in the same age group. This study indicates that the timing of HMT initiation is crucial, and treatment plans should be tailored to the patient’s age and racial background.
After reviewing the study, experts commented that it is promising to see evidence suggesting that HMT for breast cancer may also reduce the risk of Alzheimer’s and related dementias, especially in younger patients. However, the increased risk for older patients and variability by race highlight the need for personalized treatment plans. Researchers should continue to explore ways to lower dementia risk, as Alzheimer’s and other dementias severely impact patients’ quality of life and place a significant burden on caregivers and healthcare systems. Further research should focus on mechanisms behind racial disparities observed in the study, specific types of HMT and their effects on dementia risk, long-term studies to confirm findings, and guidelines for personalized HMT treatment plans considering individual patient factors.
One expert noted that while this study suggests an association between HMT and reduced dementia risk, further research is needed to determine whether the medication is directly responsible for this effect. Factors such as the type of breast cancer and chemotherapy received by patients may also influence cognitive outcomes and dementia risk. Future studies should investigate different types of HMT and their effects on cognitive decline, as well as explore the biological mechanisms behind any observed protective effects. Overall, while the study is intriguing, more research is required to definitively conclude that HMT decreases the risk of dementia.
