Mammographic density changes during different postmenopausal hormone replacement therapies

Objective: To determine the degree of change in mammographic breast densiti es during different types of postmenopausal hormone replacement therapies. Design: A retrospective study. Setting: Ege University Hospital. Patient(s): The mammographies of 216 women on various postmenopausal hormon e replacement therapies were evaluated. Intervention(s): Estrogen alone (n=76) or estrogen in cyclic (n=44) or cont inuous (n=61) combination with progestin or tibolone-only (n=35) replacemen t therapies were used. Mammographic density was quantified according to the Wolfe classification in patients with different hormone replacement regime ns. Main Outcome Measure(s): Mammographic density changes were interpreted. Result(s): An increase in mammographic density was much more common among w omen receiving continuous combination hormone replacement therapy 31.1% (19 of 61) than among those receiving estrogen-only 3.9% (3 of 76) treatment. There were no significant mammographic breast density changes among women r eceiving cyclic continuous combination hormone replacement therapy or tibol one-only treatment. The increase in density was apparent already at first v isit after the start of hormone replacement therapy. In continuous combined postmenopausal hormone replacement therapy with norethisterone acetate, th e increase in mammographic density was 34.1% (15 of 44), followed by medrox yprogesterone acetate 23.5% (4 of 17). Conclusion(s): Our findings show that mammographic breast density changes r elated to postmenopausal hormone replacement therapy are dependent on the s elected hormone regimen. The continuous administration of the progestin com ponent of the combined-hormone replacement therapy seems to effect the brea st density most. (Fertil Steril(R) 2001;76:445-50. (C) 2001 by American Soc iety for Reproductive Medicine.).