Review: use of hormone replacement therapy in the past 5 years is associated with an increased risk of breast cancer
Question Is hormone replacement therapy (HRT) associated with an increased risk of breast cancer?
Studies were identified from review articles, literature searches, and colleagues.
Studies were selected if they included ≥100 women with breast cancer and if information was obtained on the use of HRT and reproductive and menopausal history.
Data were collected from the investigators for individual women on their use of HRT and hormonal contraceptives, sociodemographic factors, family history of breast cancer, height, weight, age at menarche, reproductive history, gynaecological surgery, menopausal status, age at menopause, and tumour spread for those who had breast cancer.
51 studies from 21 countries involving 52 705 women with invasive breast cancer and 108 411 women without breast cancer were included (81% of eligible studies). Meta-analyses were stratified by study, study centre, age at diagnosis, time since menopause, body mass index, parity, and, when appropriate, age of the woman at first birth. The main analyses were based on 53 865 postmenopausal women (17 949 with breast cancer and 35 916 without breast cancer) …