## Abstract Increasing use of HRT over the last 2 decades could have contributed to the increasing incidence of cancer in women. Our aim was to investigate the relation between use of HRT and risk of hormone‐dependent cancers in a Norwegian cohort of women. The Norwegian Women and Cancer (NOWAC) st
Hormone replacement therapy and breast cancer in former users of oral contraceptives—The Norwegian Women and Cancer study
✍ Scribed by Eiliv Lund; Kjersti Bakken; Vanessa Dumeaux; Vegard Andersen; Merethe Kumle
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- French
- Weight
- 66 KB
- Volume
- 121
- Category
- Article
- ISSN
- 0020-7136
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Combined estrogen–progestin menopausal therapy (HRT) and combined estrogen–progestin contraceptives (OC) both increase breast cancer risk during current use and a few years after. We investigated risk of breast cancer in women who were users of HRT dependant on former history of OC use in a large, national population‐based cohort study, the Norwegian Women and Cancer study (NOWAC). Exposure information was collected through postal questionnaires. Based on follow‐up of 30,118 postmenopausal women by linkage to national registers of cancer, deaths, and emigration we revealed 540 incident breast cancer cases between 1996 and 2004. Compared to never users of either drugs current use of HRT gave a significant (p = 0.002) higher risk of breast cancer in former OC users, RR = 2.45 (95% CI 1.92–3.12), than among never users of OCs, RR = 1.67 (1.32–2.12). Relative risk of current use of HRT was similar for estrogen only and combinations with progestin added in ever users of OCs. The increased risk of breast cancer in current HRT users with a history of former OC use could have potential great impact on postmenopausal breast cancer risk as the proportion of postmenopausal women with former OC use will continue to increase. © 2007 Wiley‐Liss, Inc.
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