Progestin may modify the effect of low-dose hormone therapy on mammographic breast density.
OBJECTIVE
To evaluate the effect on breast density of two low-dose hormone therapy regimens identical in their estrogen component but different in the progestin.


METHODS
A total of 81 non-hysterectomized postmenopausal women were allocated either to 17beta-estradiol 1 mg and norethisterone acetate 0.5 mg (E2/NETA, n = 43) or to 17beta-estradiol 1 mg and drospirenone 2 mg (E2/DRSP, n = 38). Treatment was continuous and lasted 12 months. The main outcomes were the changes in breast density according to the Wolfe classification between baseline and 12-month mammograms.


RESULTS
Involution of the fibroglandular tissue was not seen in either of the treatment groups. Under E2/NETA, breast density increased in seven women (16.3%). In contrast, only three women (7.9%) exhibited a density increase under E2/DRSP.


CONCLUSIONS
Although hormone therapy appears to suspend breast involution, it does not increase breast density in the majority of treated women. Progestins differing in pharmacological properties may have a variable impact on breast density.
Panoulis
C
C
2nd Department of Obstetrics and Gynecology, University of Athens, Aretaieion Hospital, Athens, Greece.
Lambrinoudaki
I
I
Vourtsi
A
A
Augoulea
A
A
Kaparos
G
G
Aravantinos
L
L
Christodoulakos
G
G
Creatsas
G
G
D000328:Adult; D000736:Androstenes / Q000008:administration & dosage*; D001940:Breast / Q000187:drug effects; D003280:Contraceptives, Oral, Synthetic / Q000008:administration & dosage*; D004958:Estradiol / Q000008:administration & dosage; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D000451:Mineralocorticoid Receptor Antagonists / Q000008:administration & dosage*; D009640:Norethindrone / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000077563:Norethindrone Acetate; D017698:Postmenopause
D000736:Androstenes; D003280:Contraceptives, Oral, Synthetic; D004967:Estrogens; D000451:Mineralocorticoid Receptor Antagonists; D004958:Estradiol; D000077563:Norethindrone Acetate; C035144:drospirenone; D009640:Norethindrone