Hormone therapy for breast cancer may reduce dementia risk; benefit varies by age, race
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Women with breast cancer who underwent hormone-modulating therapy exhibited a reduced risk for Alzheimer’s disease and related dementias, according to results of a retrospective cohort study.
The extent of the benefit varied by age and race, results showed.
“With earlier breast cancer diagnosis and advances in treatment, there are more and more breast cancer survivors,” researcher Chao Cai, PhD, assistant professor of clinical pharmacy and outcomes sciences in the College of Pharmacy at University of South Carolina, told Healio. “This raises concerns about the long-term treatment implications, especially in terms of cognitive function. Our findings are a great addition to the [evidence] on this topic and also remind health care providers that there is no one-size-fits-all [strategy]. It emphasizes the importance of a personalized treatment care plan.”
Many patients with hormone receptor-positive breast cancer receive hormone-modulating therapy. Prior research into the potential links between hormone-modulating therapy and risk for Alzheimer’s disease or related dementia is limited, and previous studies have yielded mixed results.
Some studies — including clinical trials and observational studies — showed hormone modulating-therapy could have a protective effect, whereas others showed hormone-modulating therapy could negatively affect cognitive function, Cai said. Some studies showed no association.
“There is no clear conclusion regarding this association,” Cai said. “The goal of our study was to bring additional evidence to this topic.”
Cai and colleagues used the SEER-Medicare linked database to identify 18,808 women (87.9% white; 6.7% Black) aged 65 years or older diagnosed with breast cancer between 2007 and 2009. Eligible individuals had no history of Alzheimer’s disease or related dementias, and they had not used hormone-modulating therapy prior to breast cancer diagnosis.
Approximately two-thirds (65.7%) of individuals in the cohort received hormone-modulating therapy within 3 years of breast cancer diagnosis.
Over 12-year follow-up, 23.7% of participants who received hormone-modulating therapy developed Alzheimer’s disease or related dementias, as did 27.9% of those who did not receive hormone-modulating therapy.
Results showed a statistically significant reduction in risk for Alzheimer’s disease or related dementias among those who received hormone-modulating therapy (HR = 0.93; 95% CI, 0.88-0.98).
The risk reduction appeared greatest among women aged 65 to 69 years (HR = 0.48; 95% CI, 0.43-0.53), then diminished with older age.
Researchers observed this trend among women who self-identified as Black (age 65 to 74 years, HR = 0.76; 95% CI, 0.62-0.92; age 75 years or older, HR = 0.81; 95% CI, 0.67-0.98) and those who self-identified as white (age 65 to 74 years, HR = 0.89; 95% CI, 0.81-0.97; age 75 years or older, HR = 0.96; 95% CI, 0.9-1.02).
Results also showed risk differences by race (all Black women; HR = 0.78; 95% CI, 0.65-0.94; all white women, HR = 0.94; 95% CI, 0.89-0.99; P for interaction of hormone-modulating therapy and race < .001).
Results showed no significant associations between hormone-modulating therapy and risk among women of other races, though investigators noted some race- and age-based associations varied by type of hormone-modulating therapy.
“Our study emphasizes the importance of personalized treatment plans and shared decision-making between the patient and the health care provider,” Cai said. “We also want to improve our medical knowledge about the association between hormone-modulating therapy and Alzheimer’s disease or related dementia. We need to think about patients’ individual characteristics and tailor treatment to maximize benefits and minimize treatment risks.”
For more information:
Chao Cai, PhD, can be reached at caic@mailbox.sc.edu.
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