23 January 2023
Summary
Recently, Rye et al. [1] investigated the association of the use of tamoxifen with the risk of endometrial cancer and other uterine diseases in premenopausal women with breast cancer (BC). For this the authors carried out a nationwide, population-based, retrospective longitudinal cohort study with an 18-year study period using data obtained from the Korean National Health Insurance Service. Premenopausal women aged 20 to 50 years with BC diagnoses between January 2003 and December 2018 were included, with data analysis being performed from April to December 2021. Tamoxifen treatment was the main exposure variable and outcomes included: the incidence of uterine diseases, including endometrial cancer (EC), endometrial hyperplasia (EH), endometrial polyps (EP), and other uterine cancers. The incidence of uterine diseases was compared between tamoxifen users and non-users. A total 78,320 female participants were included (mean age 42.1), 34,637 (44.2%) were tamoxifen users and 43,683 (55.8%) were non-users. During the mean follow-up 6.13 years, among tamoxifen users the incidence of newly diagnosed EP, EH, EC and uterine cancers was 20.13, 13.49, 2.01 and 0.45 cases per 1,000 person-years, respectively. The risk of EC was higher in the tamoxifen group than in the control group after adjusting for age, body mass index, history of diabetes, and other co-variates. The authors conclude that premenopausal Korean women with BC who received tamoxifen as adjuvant hormone therapy, as compared to those who did not, had a significantly increased risk of studied uterine diseases, suggesting that clinicians should consider this risk in premenopausal women.