Null association between tamoxifen use and dementia in Danish breast cancer patients
Menée à partir de données de registres médicaux danois portant sur 16 419 patientes atteintes d'un cancer du sein diagnostiqué entre 1990 et 2004, cette étude ne montre pas d'association entre l'utilisation du tamoxifène ou d'autres traitements endocriniens et le risque de démence
Background : Concerns have been raised about the risk of dementia associated with anti-estrogen adjuvant therapy in breast cancer, but study results have been inconsistent. We examined whether tamoxifen or other endocrine therapy was associated with dementia risk in a large population of breast cancer patients. Methods : We used Danish nationwide medical registries to identify breast cancer patients diagnosed between 1990 and 2004, use of endocrine therapy and subsequent diagnoses of dementia. We used Cox regression to estimate the risk of dementia among patients who received five years of tamoxifen or other endocrine therapies. Results : The study included 16,419 breast cancer patients. In this cohort, 37% were unexposed to endocrine therapy, 9% had five years of tamoxifen therapy and 54% had other endocrine regimens, some of them containing tamoxifen for less than five years with subsequent aromatase inhibitor therapy. Tamoxifen therapy was associated with a near-null risk of dementia (hazard ratio (HR): 1.4, 95% CI: 1.0, 1.9), and a null association was observed after death was taken into account as a competing risk (Sub-HR=1.0, 95%CI: 0.76, 1.4). Conclusions : No clinically relevant association between use of tamoxifen or other endocrine therapy and risk of dementia was observed.