From the Journals

Breast Cancer Hormone Therapy May Protect Against Dementia


 

TOPLINE:

Hormone-modulating therapy for breast cancer may protect older women from Alzheimer’s disease and related dementias, although the protective effect varies by age and race, with the greatest benefit seen in younger Black women.

METHODOLOGY:

  • Hormone-modulating therapy is widely used to treat hormone receptor–positive breast cancer, but the cognitive effects of the treatment, including a potential link to dementia, remain unclear.
  • To investigate, researchers used the SEER-Medicare linked database to identify women aged 65 years or older with breast cancer who did and did not receive hormone-modulating therapy within 3 years following their diagnosis.
  • The researchers excluded women with preexisting Alzheimer’s disease/dementia diagnoses or those who had received hormone-modulating therapy before their breast cancer diagnosis.
  • Analyses were adjusted for demographic, sociocultural, and clinical variables, and subgroup analyses evaluated the impact of age, race, and type of hormone-modulating therapy on Alzheimer’s disease/dementia risk.

TAKEAWAY:

  • Among the 18,808 women included in the analysis, 66% received hormone-modulating therapy and 34% did not. During the mean follow-up of 12 years, 24% of hormone-modulating therapy users and 28% of nonusers developed Alzheimer’s disease/dementia.
  • Overall, hormone-modulating therapy use (vs nonuse) was associated with a significant 7% lower risk for Alzheimer’s disease/dementia (hazard ratio [HR], 0.93; P = .005), with notable age and racial differences.
  • Hormone-modulating therapy use was associated with a 24% lower risk for Alzheimer’s disease/dementia in Black women aged 65-74 years (HR, 0.76), but that protective effect decreased to 19% in Black women aged 75 years or older (HR, 0.81). White women aged 65-74 years who received hormone-modulating therapy (vs those who did not) had an 11% lower risk for Alzheimer’s disease/dementia (HR, 0.89), but the association disappeared among those aged 75 years or older (HR, 0.96; 95% CI, 0.90-1.02). Other races demonstrated no significant association between hormone-modulating therapy use and Alzheimer’s disease/dementia.
  • Overall, the use of an aromatase inhibitor or a selective estrogen receptor modulator was associated with a significantly lower risk for Alzheimer’s disease/dementia (HR, 0.93 and HR, 0.89, respectively).

IN PRACTICE:

Overall, the retrospective study found that “hormone therapy was associated with protection against [Alzheimer’s/dementia] in women aged 65 years or older with newly diagnosed breast cancer,” with the decrease in risk relatively greater for Black women and women younger than 75 years, the authors concluded.

“The results highlight the critical need for personalized breast cancer treatment plans that are tailored to the individual characteristics of each patient, particularly given the significantly higher likelihood (two to three times more) of Black women developing [Alzheimer’s/dementia], compared with their White counterparts,” the researchers added.

SOURCE:

The study, with first author Chao Cai, PhD, Department of Clinical Pharmacy and Outcomes Sciences, University of South Carolina, Columbia, was published online on July 16 in JAMA Network Open.

LIMITATIONS:

The study included only women aged 65 years or older, limiting generalizability to younger women. The dataset lacked genetic information and laboratory data related to dementia. The duration of hormone-modulating therapy use beyond 3 years and specific formulations were not assessed. Potential confounders such as variations in chemotherapy, radiation, and surgery were not fully addressed.

DISCLOSURES:

Support for the study was provided by the National Institutes of Health; Carolina Center on Alzheimer’s Disease and Minority Research pilot project; and the Dean’s Faculty Advancement Fund, University of Pittsburgh, Pennsylvania. The authors reported no relevant disclosures.

A version of this article first appeared on Medscape.com.

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