Hormone Therapy & Breast Cancer: Alzheimer’s Risk?

Researchers examined the relationship between hormone-modulating therapy (HMT) for treating breast cancer and women 65 years of age or older’s risk of Alzheimer’s disease and related dementias (ADRD), a collection of cognitive disorders that cause memory loss and impaired thinking.

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Context
In the United States (US), 83% of invasive instances of breast cancer occur in women 50 years of age and older. Breast cancer is the most prevalent malignancy among women to receive a diagnosis. While the annual incidence of breast cancer has increased by 0.5% since 2000, almost 2.5 million survivors 65 years of age and beyond have resulted from lowering mortality rates.

Concerns over treatment-related side effects, in particular the possibility of ADRD, are raised by this increase. Although HMT has increased survival rates, it is yet unknown how treatment may affect cognitive function and the risk of ADRD.

The contradictory results regarding HMT’s effect on ADRD risk in breast cancer survivors require more investigation.

About the study
The study cohort comprised sociocultural, demographic, and clinical data for people with breast cancer and was derived from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. The database allows for a thorough evaluation throughout a patient’s coverage term by connecting Medicare claims data with SEER cancer registry data.

Women 65 years of age and older who were diagnosed with breast cancer for the first time between 2007 and 2009 were included; those having a history of HMT usage or ADRD were not.

Using the National Drug Code (NDC) and Healthcare Common Procedure Coding System (HCPCS) codes for selective estrogen receptor modulators (SERMs), aromatase inhibitors (AIs), and selective estrogen receptor degraders (SERDs), as well as starting at least one HMT medication within three years of diagnosis, was the definition of HMT exposure.

Time to ADRD was the result, which was determined by using the International Classification of Diseases, Ninth Revision (ICD-9) and ICD-10 classifications.

Utilizing t-tests or χ2 tests, baseline characteristics were compiled and assessed. Following a propensity score weighting approach to balance variables between groups, patients were assigned to the HMT group depending on whether or not they were HMT initiators. To counteract the illusion of immortality, death was considered a competing risk that was assigned to the control group.

Taking into account the relationships between age and race, two models were utilized to assess the relationship between HMT and ADRD risk.

Subgroup analysis looked at differences between different HMT types and racial groups. SAS and R were used to run the statistical analysis, with a two-sided P value of.05.

In conclusion
In conclusion, hormone-positive breast cancer must be treated with HMT, however this treatment raises questions regarding cognitive impairment.

The findings of the research on HMT’s relationship to ADRD risk are conflicting. The study’s large cohort revealed a 7% relative risk decrease in ADRD among HMT users, which was supported by a number of analytical techniques.

The risk of ADRD is strongly influenced by age and race; younger Black women have the most protective effects, which decrease but do not disappear with age.

White women in their younger years likewise gain, however this impact wanes around 75 years of age. ADRD risk is also influenced by the kind of HMT, emphasizing the necessity for individualized treatment regimens.

For more information: Alzheimer Disease and Related Dementia Following Hormone-Modulating Therapy in Patients With Breast Cancer,  JAMA Network Open, doi:10.1001/jamanetworkopen.2024.22493