Estradiol levels in women with hormone receptor-positive advanced breast cancer on fulvestrant therapy.

ABSTRACT:

Background

Limited data are available on estradiol (E2) levels during fulvestrant treatment in women with hormone receptor-positive breast cancer.

Methods

We measured plasma E2 levels in women receiving fulvestrant using liquid chromatography-tandem mass spectrometry. Patient characteristics and treatment efficacy were assessed in relation to E2 levels. A cutoff of 2.72 pg/mL was used because it defines E2 suppression and postmenopausal status.

Results

A total of 69 women were enrolled, with a median age of 48 years. The median duration of fulvestrant treatment was 11.6 months. The median E2 level across the cohort was 3.60 pg/mL, with considerable interindividual variability (range: 1.11-526.13 pg/mL), and 49 women (71.0%) had E2 levels above 2.72 pg/mL. Eleven women

SUBMITTER: Dai S 

PROVIDER: S-EPMC12715405 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature