Association of Endocrine Therapy and Dementia in Women with Breast Cancer

• Published in: Breast cancer targets and therapy Vol. 13; pp. 219 - 224
• Main Authors: Thompson, Mikayla R, Niu, Jiangong, Lei, Xiudong, Nowakowska, Malgorzata, Wehner, Mackenzie R, Giordano, Sharon H, Nead, Kevin T
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01.01.2021; Taylor & Francis Ltd; Dove; Dove Medical Press
• Subjects: Analysis; aromatase inhibitors; Bias; Breast cancer; Cancer; Cancer therapies; Care and treatment; Chemotherapy; Dementia; Dementia disorders; Endocrine therapy; Epidemiology; Estrogen; Estrogens; Health aspects; Hormones; Investigations; Medical diagnosis; Medicare; Metastases; Metastasis; Mortality; Original Research; Regression analysis; selective estrogen receptor modulators; Women; Womens health; Taiwan; selective estrogen receptor modulators; breast cancer; dementia; aromatase inhibitors; endocrine therapy
• DOI: 10.2147/BCTT.S300455
• ISSN: 1179-1314

Prior studies have reported differing results regarding the association between endocrine therapy (ET) in the treatment of breast cancer and dementia risk. However, existing findings may be limited by common sources of bias and confounding. Here we investigate the association of ET utilized in the definitive setting to treat non-metastatic breast cancer with dementia risk accounting for multiple potential sources of bias and confounding. We conducted a retrospective study in SEER-Medicare of women aged ≥ 66 years with non-metastatic breast cancer. We examined the risk of all-cause dementia among ET users versus non-ET users using multivariable regression models, accounting for the competing risk of death, and using a start of the follow-up period as 12-months following breast cancer diagnosis for both groups to avoid immortal time bias. Among 25,777 individuals there were 2,869 incident dementia cases. We found a statistically significantly decreased risk of any dementia among ET users in unadjusted and adjusted models that completely attenuated when accounting for the competing risk of death (hazard ratio, 0.98; 95% confidence interval, 0.90-1.07). When accounting for common sources of bias and confounding we did not find evidence to support an association between ET in the definitive treatment of non-metastatic breast cancer and dementia risk. These results suggest that ET may not be associated with dementia risk.