对长期雌二醇 (E2) 抑制的了解有限，这对芳香酶抑制剂 (AI) 辅助治疗的有效性提出了挑战，需要全面的血清 E2 监测来解决这个问题。因此，我们的目的是调查接受辅助AI治疗的女性的血清E2水平，并评估此类监测的意义。在这项前瞻性队列研究中，我们招募了接受辅助AI治疗的女性，包括接受卵巢功能抑制（OFS）的女性。使用高效液相色谱-串联质谱法 (LC-MS/MS) 测量血清 E2 水平。主要终点是 E2 水平超过 2.72 pg/mL 的女性比例，表明 AI 疗法抑制效果不充分。共有 706 名患者入组，其中包括 482 名患有 OFS 与 AI 联合治疗的女性。其中，116 名女性（16.4%）的 E2 水平超过 2.72 pg/mL。大多数血清 E2 升高 (77.6%) 发生在开始内分泌治疗的头两年内。年龄较小、既往未接受化疗、当前治疗方案持续时间较短以及促卵泡激素 (FSH) 水平较低与 E2 抑制不足相关。 AI辅助治疗后血清E2浓度呈现动态变化和偶尔反弹。尽管接受AI辅助治疗近两年，仍有一定比例的患者未能达到足够的E2抑制阈值。我们的研究结果强调了在辅助 AI 治疗期间监测血清 E2 水平的重要性，特别是在头两年内。为了更全面地理解 E2 监测，必须进行进一步的研究。版权所有 © 2024 作者。由爱思唯尔有限公司出版。保留所有权利。

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.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.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.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.Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.