Incidence of breast cancer in a 22-year study of women receiving estrogen-progestin replacement therapy

Objective: To review the incidence of breast cancer in a continuous 22-year study of conjugated estrogen-medroxyprogesterone acetate hormone replacement therapy. Methods: Eighty-four pairs of continuously hospitalized postmenopausal women who were matched for age, smoking history, and medical diagnosis were treated with estrogen-progestin hormone replacement therapy or placebo in a prospective and double-blind manner for 10 years. In the subsequent 12 years, the women were offered the choice of starting, stopping, or continuing hormone replacement therapy