Oestrogen plus progestogen increased risk of breast cancer in postmenopausal women
Q In postmenopausal women, does oestrogen plus progestogen hormone therapy increase the risk of abnormal mammographic results and diagnosis of breast cancer?
METHODS
Design:
randomised, placebo controlled trial (Women’s Health Initiative).
Allocation:
concealed.
Blinding:
blinded (clinicians, participants, data collectors, outcome assessors, and monitoring committee).
Follow up period:
mean 5.6 years.
Setting:
40 US clinical centres.
Patients:
16 608 postmenopausal women who were 50–79 years of age (mean age 63 y). Exclusion criteria: previous hysterectomy, breast cancer, or probable survival <3 years.
Interventions:
1 daily tablet of conjugated equine oestrogen, 0.625 mg, and medroxyprogesterone acetate, 2.5 mg (Prempro, Wyeth Ayerst, Philadelphia, PA, USA) (n = 8506) or placebo (n = 8102).
Outcomes:
incidence of breast cancer (total, invasive, and in situ) and …
