This study is a prospective observational cohort study aimed at developing a clinical model based on dynamic changes in anti-Müllerian hormone (AMH) to predict ovarian reserve in perimenopausal women with hormone receptor-positive breast cancer.

The study will enroll approximately 300 women aged 45-55 years with perimenopausal status confirmed by menstrual history and hormone levels (FSH 10-40 IU/L, E2 >20 pg/mL). Participants will be stratified by treatment regimen: (A) chemotherapy plus endocrine therapy, (B) chemotherapy plus targeted therapy plus endocrine therapy, and (C) endocrine therapy alone.

Blood samples will be collected at seven time points to measure AMH, FSH, E2, and LH. Menstrual patterns and menopausal symptoms will be recorded prospectively. The primary outcome is the association between dynamic AMH changes and the occurrence of menopause. A predictive model will be constructed using LASSO regression and Cox proportional hazards models, with internal validation by bootstrap resampling.

The goal is to develop a clinically applicable tool to guide endocrine therapy decisions-including the duration of ovarian function suppression (OFS), choice between tamoxifen and aromatase inhibitors (AIs), and selection of CDK4/6 inhibitors-as well as to provide individualized fertility preservation counseling for perimenopausal breast cancer patients.

Background and Rationale Breast cancer is the most common malignancy among women in China, with a peak incidence at 45-55 years-approximately 10 years younger than in Western populations. Perimenopausal women account for more than 35% of all breast cancer cases in China. Chemotherapy-induced ovarian failure occurs in 40% to 80% of patients over age 40, significantly impacting quality of life and long-term health outcomes.

Anti-Müllerian hormone (AMH) is considered the most stable biomarker for ovarian reserve. International studies have demonstrated that baseline AMH levels predict chemotherapy-induced amenorrhea (CIA) and ovarian function recovery, with area under the curve (AUC) values ranging from 0.79 to 0.86. However, predictive performance declines in women over age 40 (AUC 0.678). Moreover, most existing studies focus on younger patients, and data specific to the perimenopausal population remain scarce. In addition, the standardization of AMH measurement and the integration of serial dynamic monitoring into clinical prediction models have not been well established.

Study Objectives

1. The primary objective is to develop a predictive model based on dynamic changes in AMH to assess ovarian reserve in perimenopausal breast cancer patients undergoing adjuvant therapy. Secondary objectives include:
2. Characterizing the trajectory of AMH changes during and after chemotherapy and/or endocrine therapy;
3. Identifying independent predictors of menopause occurrence in this population;
4. Evaluating the potential clinical utility of the model to guide endocrine therapy decisions and fertility preservation counseling.

Study Design This is a single-center, prospective observational cohort study conducted at Liaoning Cancer Hospital, China. The study will enroll approximately 300 participants. No investigational drugs or devices are involved.

Study Population and Eligibility

Inclusion criteria:

1. Female, aged 45-55 years;
2. Histologically confirmed hormone receptor-positive breast cancer;
3. Perimenopausal status defined as: (a) last menstrual period within 3 months prior to enrollment; and (b) FSH 10-40 IU/L and E2 >20 pg/mL;
4. Scheduled to receive adjuvant chemotherapy and/or endocrine therapy;
5. Willing to undergo serial blood sampling and complete menstrual diaries;
6. Able to provide written informed consent.

Exclusion criteria:

1. Postmenopausal status;
2. Prior bilateral oophorectomy or pelvic radiotherapy;
3. Severe hepatic or renal dysfunction;
4. ER-negative and PR-negative breast cancer;
5. Conditions affecting ovarian hormone secretion (e.g., ovarian tumors, polycystic ovary syndrome, pituitary tumors);
6. Current pregnancy, lactation, or planned pregnancy during follow-up;
7. Use of hormonal intrauterine devices;

9.Prior use of GnRH agonists or aromatase inhibitors.

Treatment Stratification

Participants will be stratified into three groups according to planned treatment:

Group A (n ≈ 100): Chemotherapy followed by endocrine therapy (tamoxifen or aromatase inhibitor ± ovarian function suppression); Group B (n ≈ 100): Chemotherapy plus targeted therapy (anti-HER2) followed by endocrine therapy; Group C (n ≈ 100): Endocrine therapy alone.

Study Procedures

Blood samples will be collected at seven time points: at baseline (before treatment initiation), during treatment, and during follow-up. AMH, FSH, E2, and LH levels will be measured using standardized enzyme-linked immunosorbent assays (ELISA). All samples will be processed within 2 hours of collection and stored at -80°C until analysis. Repeated freeze-thaw cycles will be limited to a maximum of two.

Menstrual patterns will be recorded using patient-completed menstrual diaries. Menopausal symptoms will be assessed using a validated menopausal symptom rating scale at each follow-up visit.

Outcomes

The primary outcome is the association between dynamic AMH changes and the occurrence of menopause (defined as 12 consecutive months of amenorrhea in the absence of other causes). Secondary outcomes include:

1. Time to menopause;
2. Resumption of menstrual bleeding after treatment;
3. Changes in FSH, E2, and LH levels over time;
4. Quality of life and menopausal symptom scores.

Statistical Analysis

Data analysis will be performed using R software. LASSO regression will be applied for variable selection. A predictive nomogram will be constructed using Cox proportional hazards models. Model performance will be assessed by discrimination (C-index/AUC) and calibration curves. Internal validation will be conducted using bootstrap resampling with 1,000 repetitions. The target model performance is AUC >0.80.

Data Monitoring and Quality Control

A quality control team will review study progress, data completeness, and sample handling quarterly. Electronic case report forms (eCRFs) will be used for data collection, with double data entry and cross-verification. All data will be stored on a secure hospital server with regular backups.

Ethical Considerations

This study will be conducted in accordance with the Declaration of Helsinki and Chinese regulations on biomedical research involving human subjects. The protocol has been reviewed and approved by the Ethics Committee of Liaoning Cancer Hospital. All participants will provide written informed consent prior to enrollment. Participant confidentiality will be strictly maintained.

Study Duration

The total study duration is approximately 48 months, comprising:

Enrollment period: 24 months (anticipated July 2026 - June 2028);

Follow-up period: up to 36 months;

Data analysis and manuscript preparation: 12 months (July 2028 - June 2029).

Inclusion Criteria:

1. Female, aged 45-55 years
2. Histologically confirmed hormone receptor-positive breast cancer
3. Perimenopausal status defined as: (a) last menstrual period within 3 months prior to enrollment; and (b) FSH 10-40 IU/L and E2 >20 pg/mL
4. Scheduled to receive adjuvant chemotherapy and/or endocrine therapy
5. Willing to undergo serial blood sampling and complete menstrual diaries
6. Able to provide written informed consent

Exclusion Criteria:

1. Postmenopausal status
2. Prior bilateral oophorectomy or pelvic radiotherapy
3. Severe hepatic or renal dysfunction
4. Estrogen receptor (ER)-negative and progesterone receptor (PR)-negative breast cancer
5. Conditions affecting ovarian hormone secretion (e.g., ovarian tumors, polycystic ovary syndrome, pituitary tumors)
6. Current pregnancy, lactation, or planned pregnancy during follow-up
7. Use of hormonal intrauterine devices
8. Prior use of GnRH agonists or aromatase inhibitors

This study will enroll approximately 300 perimenopausal women aged 45-55 years with histologically confirmed hormone receptor-positive breast cancer treated at Liaoning Cancer Hospital. Participants will be stratified into three groups based on treatment regimen: chemotherapy plus endocrine therapy (Group A), chemotherapy plus targeted therapy plus endocrine therapy (Group B), and endocrine therapy alone (Group C). All participants must meet perimenopausal status criteria defined by menstrual history and hormone levels (FSH 10-40 IU/L, E2 >20 pg/mL) at enrollment.

Individual participant data will not be shared due to confidentiality and privacy protection requirements under Chinese regulations and institutional policies. The informed consent obtained from participants does not include provisions for data sharing with external researchers. Additionally, the data contain sensitive personal health information including hormone levels, menstrual records, and menopausal symptoms, which are subject to strict data protection standards.