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. 2024 Dec:78:103818.
doi: 10.1016/j.breast.2024.103818. Epub 2024 Sep 29.

Clinical significance of serum estradiol monitoring in women receiving adjuvant aromatase inhibitor for hormone receptor-positive early breast cancer

Shuqin Dai  1 , Xingping Wu  1 , Xuefang Huang  2 , Jibin Li  3 , Xi Wang  4 , Shusen Wang  5 , Jun Tang  4 , Yanxia Shi  5 , Xiaoming Xie  4 , Fei Xu  5 , Peng Liu  4 , Jiajia Huang  5 , Xinhua Xie  4 , Xin An  5 , Meiting Chen  5 , Rouxi Hong  5 , Wen Xia  5 , Qiufan Zheng  5 , Kuikui Jiang  5 , Yongyi Zhong  5 , Zhongyu Yuan  5 , Yuanyuan Huang  6 , Xiwen Bi  5 , Cong Xue  7
Affiliations

Clinical significance of serum estradiol monitoring in women receiving adjuvant aromatase inhibitor for hormone receptor-positive early breast cancer

Shuqin Dai et al. Breast. 2024 Dec.

Abstract

Purpose: The limited understanding of long-term estradiol (E2) suppression poses challenges to the effectiveness of adjuvant therapy with aromatase inhibitors (AI), necessitating comprehensive serum E2 monitoring to address this issue. Therefore, our objective was to investigate serum E2 levels in women undergoing adjuvant AI treatment and evaluate the significance of such monitoring.

Patients and methods: In this prospective cohort study, we recruited women who had received adjuvant AI treatment, including those who underwent ovarian function suppression (OFS). Serum E2 levels were measured using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The primary endpoint was the proportion of women with E2 levels exceeding 2.72 pg/mL, indicating inadequate suppression achieved with AI therapy.

Results: A total of 706 patients were enrolled, including 482 women with OFS in combination with AI. Among them, 116 women (16.4 %) exhibited E2 levels exceeding 2.72 pg/mL. The majority of serum E2 elevations (77.6 %) occurred within the first two years of initiating endocrine therapy. Younger age, no prior chemotherapy, shorter duration of the current treatment regimen, and lower follicle stimulating hormone (FSH) levels were associated with inadequate E2 suppression. Serum E2 concentrations demonstrated dynamic variations and occasional rebound following adjuvant AI therapy.

Conclusions: Despite receiving adjuvant AI treatment for nearly two years, a certain proportion of patients failed to achieve the adequate threshold of E2 suppression. Our findings emphasize the significance of monitoring serum E2 levels during adjuvant AI therapy, particularly within the first two years. Further research is imperative to facilitate a more comprehensive comprehension of E2 monitoring.

Keywords: Aromatase inhibitor; Estradiol monitoring; Gonadotropin-releasing hormone agonists; Hormone receptor-positive early breast cancer; Liquid chromatography–tandem mass spectrometry.

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Conflict of interest statement

Declaration of competing interest The authors declare no potential conflicts of interest.

Figures

Fig. 1
Fig. 1
Flow chart of patients' enrollment.
Fig. 2
Fig. 2
The proportion of women with E2 >2.72 pg/mL and the corresponding time points. A) Women with AI (n = 706). B) Women with AI monotherapy (n = 224). C) Women with OFS plus AI (n = 482).
Fig. 3
Fig. 3
Dynamic variation of E2 levels and the corresponding time points. The samples exhibiting elevated E2 levels are indicated by red lines. The samples exhibiting decreased E2 levels are indicated by green lines.
See this image and copyright information in PMC

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