Hormone-modulating therapy (HMT) has long been a cornerstone in the treatment of hormone receptor-positive breast cancer. However, a recent study has revealed a surprising potential benefit of this treatment: a lower risk of developing Alzheimer's disease and related dementias (ADRD). The study, led by Dr. Francesmary Modugno and her team, offers new insights into the complex relationship between breast cancer treatments and cognitive health.
Personalised Medicine in Breast Cancer Treatment
Dr. Modugno, a professor at the University of Pittsburgh and a member of Magee-Womens Research Institute and UPMC Hillman Cancer Center, emphasises the importance of personalised treatment plans for breast cancer patients. "It's not one-size-fits-all. We need to think about each individual patient to optimise outcomes and minimise risks," she says. This approach is particularly relevant in light of the study's findings, which suggest that the benefits of HMT can vary significantly depending on a patient's age and race.
The Study's Findings
The study analysed data from a federal database of women aged 65 and older who were diagnosed with breast cancer between 2007 and 2009. Among the 18,808 patients studied, 66% had received HMT within three years of their diagnosis. Over an average follow-up period of 12 years, 24% of HMT users developed ADRD compared to 28% of non-HMT users. This translates to a 7% lower risk of developing dementia for those who have undergone hormone therapy.
Age and Racial Disparities in Dementia Risk
One of the study's key findings is that the protective effect of HMT against dementia decreases with age. For patients aged 65 to 69, HMT was associated with a significant reduction in the risk of developing ADRD. However, this benefit diminished with increasing age and even reversed in patients over 80, who showed an increased risk of dementia with HMT use.
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The study also highlighted racial disparities in the benefits of HMT. Black women aged 65 to 74 who used HMT had a 24% reduction in the risk of developing ADRD, which decreased to 19% after age 75. For white women in the same age group, the risk reduction was 11%, and the protective effect disappeared entirely after age 75. These findings suggest that the timing of HMT initiation and the patient's racial background are crucial factors in determining the therapy's effectiveness in reducing dementia risk.
Understanding the Mechanisms
Dr. Chao Cai, the study's lead author and an assistant professor at the University of South Carolina College of Pharmacy, explains that estrogen has known neuroprotective effects, which could influence ADRD risk. HMT treatments work by either mimicking estrogen, influencing its production, or modulating estrogen receptor levels. These therapies might also affect the clearance of beta-amyloid proteins, the stability of tau proteins, and overall vascular health—factors closely linked to brain health and dementia risk.
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However, the study acknowledges that the exact mechanisms behind the racial disparities observed are not fully understood. Structural racism, higher lifetime stress, and other societal factors could play a role in the different outcomes seen among Black and white women. Further research is needed to explore these potential contributing factors.
Implications for Future Research and Treatment
The study's findings underscore the importance of considering individual patient factors when prescribing HMT for breast cancer. As Dr. Modugno notes, "We need to think about each individual patient to optimize outcomes and minimize risks." This approach is crucial for developing treatment plans that not only address cancer but also consider long-term cognitive health.
Future research aims to include younger women who have not yet reached menopause to better understand the link between HMT and dementia risk. The study's current limitation to patients over 65 leaves a gap in understanding the full spectrum of HMT's effects across different age groups.
Bottomline
The relationship between hormone therapy for breast cancer and the risk of dementia is complex and influenced by multiple factors, including age and race. While HMT offers a protective effect against dementia for many women, this benefit is not universal and diminishes with age. The study by Dr. Modugno and her colleagues highlights the need for personalized treatment plans and further research to unravel the mechanisms behind these findings. As the medical community continues to explore these connections, the goal remains to provide breast cancer treatments that optimize both cancer survival and long-term cognitive health.