title: Changes in breast density and circulating estrogens in postmenopausal women receiving adjuvant anastrozole.
abstract: Factors associated with an increased risk of breast cancer include prior breast cancer, high circulating estrogens, and increased breast density. Adjuvant aromatase inhibitors are associated with a reduction in incidence of contralateral breast cancer. We conducted a prospective, single-arm, single-institution study to determine whether use of anastrozole is associated with changes in contralateral breast density and circulating estrogens. Eligible patients included postmenopausal women with hormone receptor-positive early-stage breast cancer who had completed local therapy, had an intact contralateral breast, and were recommended an aromatase inhibitor as their only systemic therapy. Participants received anastrozole 1 mg daily for 12 months on study. We assessed contralateral breast density and serum estrogens at baseline, 6, and 12 months. The primary endpoint was change in contralateral percent breast density from baseline to 12 months. Secondary endpoints included change in serum estrone sulfate from baseline to 12 months. Fifty-four patients were accrued. At 12 months, compared with baseline, there was a nonstatistically significant reduction in breast density (mean change: -16%, 95% CI: -30 to 2, P = 0.08) and a significant reduction in estrone sulfate (mean change: -93%, 95% CI: -94 to -91, P < 0.001). Eighteen women achieved 20% or greater relative reduction in contralateral percent density at 12 months compared with baseline; however, no measured patient or disease characteristics distinguished these women from the overall population. Large trials are required to provide additional data on the relationship between aromatase inhibitors and breast density and, more importantly, whether observed changes in breast density correlate with meaningful disease-specific outcomes.
authors: Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors: Tatiana M
authors: TM
authors: Prowell
authors: Amanda L
authors: AL
authors: Blackford
authors: Celia
authors: C
authors: Byrne
authors: Nagi F
authors: NF
authors: Khouri
authors: Mitchell
authors: M
authors: Dowsett
authors: Elizabeth
authors: E
authors: Folkerd
authors: Karineh S
authors: KS
authors: Tarpinian
authors: Pendleton P
authors: PP
authors: Powers
authors: Laurie A
authors: LA
authors: Wright
authors: Michele G
authors: MG
authors: Donehower
authors: Stacie C
authors: SC
authors: Jeter
authors: Deborah K
authors: DK
authors: Armstrong
authors: Leisha A
authors: LA
authors: Emens
authors: John H
authors: JH
authors: Fetting
authors: Antonio C
authors: AC
authors: Wolff
authors: Elizabeth
authors: E
authors: Garrett-Mayer
authors: Todd C
authors: TC
authors: Skaar
authors: Nancy E
authors: NE
authors: Davidson
authors: Vered
authors: V
authors: Stearns
mesh_terms: D000368:Aged; D000077384:Anastrozole; D047072:Aromatase Inhibitors / Q000627:therapeutic use; D001940:Breast / Q000378:metabolism / Q000473:pathology*; D001943:Breast Neoplasms / Q000097:blood / Q000188:drug therapy / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000097:blood / Q000188:drug therapy / Q000473:pathology*; D018275:Carcinoma, Lobular / Q000097:blood / Q000188:drug therapy / Q000473:pathology*; D017024:Chemotherapy, Adjuvant; D004967:Estrogens / Q000097:blood*; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D009570:Nitriles / Q000627:therapeutic use*; D017698:Postmenopause; D011379:Prognosis; D011446:Prospective Studies; D014230:Triazoles / Q000627:therapeutic use*
chemical_list: D047072:Aromatase Inhibitors; D004967:Estrogens; D009570:Nitriles; D014230:Triazoles; D000077384:Anastrozole