Risk of dementia among postmenopausal breast cancer survivors treated with aromatase inhibitors versus tamoxifen: a cohort study using primary care data from the UK
Menée au Royaume-Uni à partir des données des dossiers médicaux électroniques en soins primaires portant sur 14 214 femmes ménopausées ayant survécu à un cancer du sein (durée de suivi : 57 102 personnes-années), cette étude évalue le risque de démence en fonction du traitement adjuvant reçu (tamoxifène ou inhibiteur d'aromatase)
Purpose : Among a cohort of postmenopausal breast cancer survivors, we aimed to compare the risk of dementia associated with aromatase inhibitor (AI) therapy versus tamoxifen. Methods : Using UK primary care electronic health records, we identified 14,214 postmenopausal breast cancer survivors (aged ≥ 54 years) with a first AI or tamoxifen prescription between January 2002 and December 2015 and no previous dementia diagnosis. Women were followed-up to identify incident cases of dementia. Cox regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) to quantify the association between AI exposure (vs. tamoxifen) and dementia, adjusted for confounders. Results : A total of 368 incident dementia cases was identified over 57,102 person-years of follow-up. The crude incidence rate of dementia was 7.46 per 1000 person-years (95% CI 6.43–8.65) among women starting endocrine treatment on an AI, and 6.32 per 1000 person-years (95% CI 5.34–7.47) among women starting on tamoxifen. After accounting for age differences and assessing other potential confounders, there was no evidence of a difference in dementia risk between exposure groups (HR for AI vs tamoxifen 1.04, 95% CI 0.83–1.03). There was no evidence of effect modification by age. Conclusion : There was no evidence for a difference in dementia risk between AI and tamoxifen users among postmenopausal breast cancer survivors.