|
|||||
|
|
Menopausal hormone therapy and breast cancer risk: Impact of different treatments. The European Prospective Investigation into Cancer and Nutrition |
|
| Authors: | Kjersti Bakken Eiliv Lund Marit Waaseth Vanessa Dumeaux Françoise Clavel‐Chapelon Alban Fabre Bertrand Hémon Sabina Rinaldi Véronique Chajes Nadia Slimani Naomi E. Allen Gillian K. Reeves Kay‐Tee Khaw Anja Olsen Anne Tjønneland Laudina Rodriguez Maria‐José Sánchez Pilar Amiano Etxezarreta Eva Ardanaz Maria‐José Tormo Petra H. Peeters Carla H. van Gils Annika Steffen Mandy Schulz Jenny Chang‐Claude Rudolf Kaaks Rosario Tumino Valentina Gallo Teresa Norat Elio Riboli Salvatore Panico Giovanna Masala Carlos A. González Franco Berrino |
| Affiliation: | 1. Department of Community Medicine, University of Troms?, Troms?, NorwayThe first two authors contributed equally to the article.Tel.: +47 77646434, Fax: +47 77644831;2. Department of Community Medicine, University of Troms?, Troms?, Norway;3. Inserm, (Institut National de la Santé et de la Recherche Médicale), ERI 20/Institut Gustave‐Roussy/University Paris, Villejuif, France;4. International Agency for Research on Cancer, Lyon, France;5. Cancer Epidemiology Unit, University of Oxford, Oxford, United Kingdom;6. Department of Public Health and Primary Care, Centre for Nutrition and Cancer, University of Cambridge, United Kingdom;7. The Danish Cancer Society, Institute of Cancer Epidemiology, Copenhagen, Denmark;8. Health and Health Care Services Council, Asturias, Spain;9. Andalusian School of Public Health, Granada and CIBER de Epidemiología y Salud Pública (CIBERESP), Spain;10. EPIC‐San Sebastian, Public Health Division of Gipuzkoa, Basque Governement. CIBER de Epidemiología y Salud Pública (CIBERESP), Spain;11. Public Health Institute of Navarra, Pamplona, Spain. CIBER Epidemiología y Salud Pública (CIBERESP), Spain;12. Department of Epidemiology, Murcia Regional Health Authority, Murcia. CIBER Epidemiología y Salud Pública (CIBERESP), Spain;13. Julius Centre for Health Sciences and Primary Care, University Medical Centre, Utrecht, The Netherlands;14. Department of Epidemiology, German Institute of Human Nutrition Rotsdam‐Rehbruecke, Nuthetal, Germany;15. Division of Cancer Epidemiology, Unit of Genetic Epidemiology, Deutsches krebsforschungszentrum, Heidelberg, Germany;16. Department of Oncology, Cancer Registry and Histopathology Unit, “Civile‐M.P.Arezzo” Hospital, Ragusa, Italy;17. Division of Epidemiology, Public Health, and Primary Care, Imperial College, London, United Kingdom;18. Department of Clinical and Experimental Medicine, Federico II University, Naples, Italy;19. Molecular and Nutritional Epidemiology Unit—Cancer Prevention and Research Institute (ISPO), Florence, Italy;20. Unit of Nutrition, Environment and Cancer, Cancer Epidemiology Research Programme, Catalan Institute of Oncology (ICO), Barcelona, Spain;21. Epidemiology Unit, National Cancer Institute, Milan, Italy |
| Abstract: | Menopausal hormone therapy (MHT) is characterized by use of different constituents, regimens and routes of administration. We investigated the association between the use of different types of MHT and breast cancer risk in the EPIC cohort study. The analysis is based on data from 133,744 postmenopausal women. Approximately 133,744 postmenopausal women contributed to this analysis. Information on MHT was derived from country‐specific self‐administered questionnaires with a single baseline assessment. Incident breast cancers were identified through population cancer registries or by active follow‐up (mean: 8.6 yr). Overall relative risks (RR) and 95% confidence interval (CI) were derived from country‐specific Cox proportional hazard models estimates. A total of 4312 primary breast cancers were diagnosed during 1,153,747 person‐years of follow‐up. Compared with MHT never users, breast cancer risk was higher among current users of estrogen only (RR: 1.42, 95% CI 1.23–1.64) and higher still among current users of combined MHT (RR: 1.77, 95% CI 1.40–2.24; p = 0.02 for combined vs. estrogen‐only). Continuous combined regimens conferred a 43% (95% CI: 19–72%) greater risk compared with sequential regimens. There was no significant difference between progesterone and testosterone derivatives in sequential regimens. There was no significant variation in risk linked to the estrogenic component of MHT, neither for oral vs. cutaneous administration nor for estradiol compounds vs. conjugated equine estrogens. Estrogen‐only and combined MHT uses were associated with increased breast cancer risk. Continuous combined preparations were associated with the highest risk. Further studies are needed to disentangle the effects of the regimen and the progestin component. |
| Keywords: | breast cancer HRT epidemiology cohort studies menopause estrogens progestins dosage |