Impact of Medroxyprogesterone Acetate by Type of Combined Oral Estrogen on Mammographic Density in Korean Postmenopausal Women / 대한폐경학회지

ABSTRACT

OBJECTIVES: We determined if the impact of medroxyprogesterone acetate (MPA) co-administered with conjugated equine estrogen (CEE) or estropipate differed on mammographic density (MMGD) in Korean postmenopausal women. METHODS: In this retrospective study, 53 healthy postmenopausal women without prior hormone therapy (HT) use were included. Smokers, habitual drinkers, women with a body mass index > or = 27 kg/m2, and women with a history of mammoplasty or breast cancer were excluded. HT using MPA (n = 26) consisted of the following two groups: CEE (n = 10) and estropipate (n = 16). Twenty-seven untreated women served as the control group. Mammography was obtained at baseline and 1 year later, and MMGD was assessed based on the breast imaging reporting and data system (BI-RADS) by one radiologist who was blinded to treatment. In addition, the change in the proportion of the dense area after HT was assessed using the J-image program. Data were analyzed with analysis of variance and chi-square or Fisher's exact test. RESULTS: There were no significant differences in baseline clinical characteristics and MMGD among the three groups. After 1 year of HT, CEE (7/10 [70%]; P < 0.001) and estropipate (3/16 [18.8%]; P = 0.002) regimens significantly elevated the BI-RADS grade compared with controls (0%), and CEE induced a greater increase in MMGD than estropipate (P = 0.033). In addition, the proportion of dense areas assessed using the J-image program increased more with the CEE regimen (7.67%) than the estropipate regimen (1.48%), but there was no statistically significant difference. CONCLUSION: Estropipate + MPA had a less stimulating effect on MMGD than CEE + MPA in Korean postmenopausal women. The change in MMGD induced with MPA might depend on the oral estrogen preparation. A further study on breast cancer risk based on combination HT is warranted.