Breast Cancer Hormone Therapy Could Reduce Risk of Alzheimer Disease

Credit: Unsplash / Esther Ann

Hormone therapy to treat breast cancer is linked to a reduced risk of Alzheimer disease and related dementias among patients aged 65 years and older, according to a recent study.

With breast cancer making up about one-third of all new cancer cases in the United States—and 83 percent of invasive breast cancers occurring in women aged at least 50 years—the new findings provide a clearer picture of how increasingly older patients with breast cancer may encounter dementia risk.

Alzheimer disease is reported in 10.8 percent of patients aged 65 years and older and is the seventh leading cause of death in the United States. The number of people with Alzheimer or a related dementia is expected to increase over time, leading to concerns about development in breast cancer survivors.

Investigators conducted a study to determine the association between hormone-modulating therapy (HMT) among breast cancer patients and dementia risk. Demographic, sociocultural, and clinical information about breast cancer patients was obtained from the Surveillance, Epidemiology, and End Results Medicare linked database.

Participants included women aged at least 65 years recently diagnosed with breast cancer between 2007 and 2009. HMT types included selective estrogen receptor modulators (SERMs), aromatase inhibitors (AIs), and selective estrogen receptor degraders (SERDs).

Alzheimer and related dementia was defined as the primary outcome of the analysis. Covariates included demographic, sociocultural, medical, and treatment variables.

There were 18,808 breast cancer patients included in the final analysis, 65.7 percent of whom had HMT exposure within three years after diagnosis and 34.3 percent did not have HMT exposure. Patients were most commonly aged 75 to 79 years, with a mean age at diagnosis of 75 years in the HMT group and 76 years in the non-HMT group.

A mean time to start HMT of nearly six months from diagnosis was reported, with 76.1 percent of HMT users initiating with AIs, 23.6 percent with SERMs, and only 0.3 percent with SERDs. HMT lasted for a mean 24 months within three years after breast cancer diagnosis.

Alzheimer and related dementias was reported in 23.7 percent of HMT users and 27.9 percent of non-HMT users by the end of the follow-up period. Death was reported in 26.4 percent and 27.5 percent, respectively. This indicated a significant association between HMT use and reduced risk of dementia.

An age-modified association between HMT and dementia risk was identified during subgroup analyses. Patients aged 65 to 69 years had the most reduced risk. In comparison, by the age of 80 years, HMT was positively associated with Alzheimer and related dementias.

These results indicated an association between HMT use and improved protection against Alzheimer and related dementias among breast cancer patients, with age considered an important modifier in this link. Investigators recommended further research to validate these associations in diverse populations.

This article was originally published on sister site Contemporary OB/GYN.