title: Pilot study of the impact of letrozole vs. placebo on breast density in women completing 5 years of tamoxifen.
abstract: Breast density, a strong risk factor for breast cancer, is reduced by the anti-estrogen, tamoxifen (TAM). We examined whether aromatase inhibitor (AI) therapy results in further reductions in breast density among women completing 5 years of TAM. Among a sample of women with early-onset breast cancer who were randomized to letrozole (LET)(n=56) or placebo (PLAC)(n=48) after 5 years of TAM, we examine the change in percent density at 9-15 months as well as a per-year change in PD by treatment group. There was no difference in the adjusted mean change (-1.0%, LET; -0.3%, PLAC (P=0.58)) or the percentage change (-2.7%, LET; -3.0%, PLAC (P=0.96)) in PD between treatment groups at 9-15 months. Results were similar for longitudinal change (-0.68% per year, LET; -0.12% per year, PLAC (P=0.23)). Breast density does not appear to be a clinically relevant biomarker in women who already have low PD following 5 years of TAM.
authors.affiliation: Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, MN, USA. vachon.celine@mayo.edu
authors.forename: C M
authors.initials: CM
authors.lastname: Vachon
authors.forename: J N
authors.initials: JN
authors.lastname: Ingle
authors.forename: V J
authors.initials: VJ
authors.lastname: Suman
authors.forename: C G
authors.initials: CG
authors.lastname: Scott
authors.forename: H
authors.initials: H
authors.lastname: Gottardt
authors.forename: J E
authors.initials: JE
authors.lastname: Olson
authors.forename: P E
authors.initials: PE
authors.lastname: Goss
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D047072:Aromatase Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D000077289:Letrozole; D008327:Mammography; D008875:Middle Aged; D009570:Nitriles / Q000008:administration & dosage / Q000627:therapeutic use*; D010865:Pilot Projects; D020845:Selective Estrogen Receptor Modulators / Q000008:administration & dosage / Q000627:therapeutic use*; D013629:Tamoxifen / Q000008:administration & dosage / Q000627:therapeutic use*; D016896:Treatment Outcome; D014230:Triazoles / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D047072:Aromatase Inhibitors; D009570:Nitriles; D020845:Selective Estrogen Receptor Modulators; D014230:Triazoles; D013629:Tamoxifen; D000077289:Letrozole