OBJECTIVES: The association of endocrine therapy (ET) and the risk of dementia has been highly debated. The aim of this systematic review is to determine the risk of dementia with ET use in women with breast cancer.

METHODS: Electronic databases such as Pubmed/MEDLINE (1966-2021), EMBASE (1947-2021), and Cochrane/CENTRAL (1908-2021) were searched to find relevant studies using keywords. Only English language studies that evaluated the risk of dementia with ET use among adult women diagnosed with breast cancer were included. Studies were independently screened by two reviewers using RAYYAN software. The review focused on study design and the main findings.

RESULTS: The systematic review identified 288 studies; nine studies met the inclusion criteria. These studies included a total of 108,024 patients, of whom 42,877 (39.7%) individuals were tamoxifen users, 32,820 (30.4%) were using aromatase inhibitors users, and raloxifene (1.8%) users amongst other endocrine therapies. Amongst the nine studies, most (seven studies) were cohort studies, one case-control design, and one cross-sectional study design. The average follow-up period of the studies was 2.5 to 7.4 years. Six studies directly compared ET to no use, while three compared the likelihood of developing various types of dementias between different ET’s. Four studies supported a decreased risk of dementia with ET with hazard ratios (HR) ranging from: 0.83 to 0.88, odds ratios (OR): 0.67 to 0.97, and relative risks (RR): 0.82- 0.89. One study reported an increased risk of dementia with ET (OR: 1.42-3.09), while four studies reported no association

CONCLUSIONS

: The systematic review found mixed evidence regarding the risk of dementia with ET use. Results varied based on dementia type, patient age at treatment, type of ET, time to follow-up, and control of confounding factors. More work is needed to address the long-term benefits/harms of ET use in women with breast cancer.