title: Oral progestagens before menopause and breast cancer risk.
abstract: We examined the relationship between use of progestagen-only before menopause (except for mini-pills) after the age of 40 and invasive breast cancer risk in 73 664 women from the French E3N cohort study (mean age at start of follow-up, 51.8 years; mean duration of follow-up, 9.1 years). A total of 2390 cases of invasive breast cancer were diagnosed during follow-up. Risk estimates were calculated using the Cox proportional hazard model. Overall, ever use of progestagen before menopause was not significantly associated with risk (relative risk (RR): 1.01, 95% confidence interval: 0.93-1.11). However, we observed a significant increase in risk associated with the duration of use (P-value for trend: 0.012), current use of progestagens for longer than 4.5 years being significantly associated with risk (RR: 1.44, 95% confidence interval: 1.03-2.00). Prolonged use of progestagens after the age of 40 may be associated with an increased risk of breast cancer and the subject needs to be investigated further.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, ERI 20, Institut Gustave Roussy, 39, rue Camille Desmoulins, F-94805 Villejuif, Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Fabre
authors.forename: A
authors.initials: A
authors.lastname: Fournier
authors.forename: S
authors.initials: S
authors.lastname: Mesrine
authors.forename: J
authors.initials: J
authors.lastname: Desreux
authors.forename: A
authors.initials: A
authors.lastname: Gompel
authors.forename: M-C
authors.initials: MC
authors.lastname: Boutron-Ruault
authors.forename: F
authors.initials: F
authors.lastname: Clavel-Chapelon
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000139:chemically induced*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D017697:Premenopause / Q000187:drug effects*; D011372:Progestins / Q000009:adverse effects*; D012307:Risk Factors; D013997:Time Factors
chemical_list: D011372:Progestins