A recent study suggests that hormone therapy for treating breast cancer could lower the risk of developing Alzheimer’s disease and similar dementias.
This research, one of the largest of its kind, was published in JAMA Network Open and found that hormone therapy was linked with a 7% reduced risk of dementia in general. However, the benefits of this therapy changed with age and race.
Francesmary Modugno, a professor at the University of Pittsburgh and part of Magee-Womens Research Institute and UPMC Hillman Cancer Center, emphasized the need for personalized treatment plans.
“It’s not one-size-fits-all. We need to think about each individual patient to optimize outcomes and minimize risks,” she said.
In breast cancer, about two-thirds of patients have tumors that grow in response to hormones like estrogen or progesterone.
For these patients, hormone therapy can slow tumor growth by blocking these hormones. While hormone therapy helps with survival rates, its effect on dementia risk has been unclear.
To gain more insight, Modugno collaborated with Chao Cai, an assistant professor at the University of South Carolina.
They used a federal database to study women aged 65 and older diagnosed with breast cancer between 2007 and 2009, who had no previous dementia diagnosis or hormone therapy before their cancer diagnosis.
Out of 18,808 patients, 66% received hormone therapy within three years of their diagnosis, while 34% did not. Over an average follow-up period of 12 years, 24% of hormone therapy users and 28% of non-users developed dementia.
The researchers adjusted their calculations to consider the risk of death with increasing age and hormone therapy duration.
They found that hormone therapy users had a lower overall risk of developing dementia, especially in women aged 65 to 69. However, this protective effect decreased with age, and for those over 80, the risk of dementia actually increased.
Chao Cai noted that younger women seem to benefit more from hormone therapy in terms of reduced dementia risk.
“The benefits of hormone therapy decreased for women aged 75 and older, particularly in those who identified as white. This suggests that the timing of hormone therapy initiation is crucial and treatment plans should be tailored to a patient’s age.”
For black women aged 65 to 74, hormone therapy reduced the risk of dementia by 24%, but this dropped to 19% after age 75. For white women of the same age range, the risk was reduced by 11%, and the benefit disappeared after age 75.
Modugno pointed out that black women generally face higher rates of breast cancer and more lifetime stress due to societal factors, which can worsen outcomes.
“We don’t know the mechanisms behind the racial disparities we saw with hormone therapy and dementia risk, but these factors could contribute. It deserves further investigation.”
There are three main types of hormone therapy: selective estrogen receptor modulators, aromatase inhibitors, and selective estrogen receptor degraders. The study found that the risk of developing dementia varied depending on the type of hormone therapy used.
Estrogen is known to have protective effects on the brain, so these therapies might influence dementia risk by mimicking estrogen, affecting estrogen production, or altering estrogen receptor levels.
Hormone therapy might also impact brain health by affecting the clearance of a protein called beta-amyloid, stabilizing tau protein, and maintaining vascular health, all of which are linked to dementia risk.
Cai explained that the relationship between hormone therapy for breast cancer and dementia risk is complex and influenced by many factors. More research is needed to understand these mechanisms and provide clearer guidance on the use of hormone therapy.
One limitation of the study was that it only included patients over 65. Future research will include younger women who haven’t reached menopause yet to further explore the link between hormone therapy and dementia risk.
Other contributors to the study included Kaowao Strickland, Sophia Knudsen, Sarah Beth Tucker, and Chandana Sai Chidrala from the University of South Carolina.
If you care about breast cancer, please read studies about a major cause of deadly breast cancer, and common blood pressure drugs may increase death risk in breast cancer.
For more information about cancer, please see recent studies that new cancer treatment could reawaken the immune system, and results showing vitamin D can cut cancer death risk.
The research findings can be found in JAMA Network Open.
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