A Real-world Study on the Compliance of OFS-assisted Endocrine Therapy for Hormone Receptor-positive(HR+) Premenopausal Breast Cancer

A Real-world Study on the Compliance of OFS-assisted Endocrine Therapy for HR+ Premenopausal Breast Cancer

The goal of this observational study is to observe the long-term prognosis of patients with early HR-positive premenopausal breast cancer. The study also aims to understand the compliance with and reasons for discontinuing adjuvant OFS endocrine therapy under different combination regimens.

The main questions it aims to answer are:

1. What are the rates of compliance with and reasons for discontinuation of adjuvant OFS endocrine therapy?
2. What is the impact of OFS treatment duration on patient prognosis?

Participants, who are already receiving OFS treatment as part of their regular medical care, will have their demographic data, treatment status, clinical outcomes, and adverse events collected over time.

Study Overview

• Status: Not yet recruiting
• Conditions: Breast Cancer Females

Detailed Description

This real-world non-interventional prospective study aims to explore the compliance and reasons for discontinuation of adjuvant OFS endocrine therapy in early HR-positive premenopausal breast cancer patients under different combination regimens of adjuvant endocrine drugs, as well as to observe the impact of the duration of OFS treatment on prognosis. This study adopts a multi-center, prospective, non-interventional design to collect approximately 300 cases of early HR-positive premenopausal breast cancer patients who received OFS treatment. After obtaining informed consent, the demographic data, breast cancer diagnosis information, comorbidities, past medical history, treatment status, clinical outcomes, and adverse events of the patients were collected. The patients were administered medication in accordance with the standard clinical drug protocols and completed follow-up according to the follow-up plan.

• Study Type: Observational
• Enrollment (Estimated): 300

Contacts and Locations

• Study Contact: Name: Yang Yu; Phone Number: +8613958013303; Email: yuyangkaiyu@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

1. Female breast cancer patients who were premenopausal at the time of surgery.
2. Newly diagnosed patients with invasive breast cancer, TNM stage I-III.
3. HR-positive (defined as ER ≥ 10% and/or PR ≥ 10%).
4. Patients who have undergone radical mastectomy and are planning to receive OFS treatment.
5. Have received (neo)adjuvant chemotherapy and radiotherapy.
6. ECOG PS score of 0-1.
7. Complete medical records.
8. Willing to accept long-term follow-up.
9. Any adverse events that occurred during adjuvant chemotherapy (if applicable) have recovered or decreased to grade 1 (according to CTCAE v5.0) at the start of OFS treatment.

Description

Inclusion Criteria:

1. Female breast cancer patients who were premenopausal at the time of surgery.
2. Newly diagnosed patients with invasive breast cancer, tumor node metastasis(TNM) stage I-III.
3. HR-positive (defined as ER ≥ 10% and/or progesterone receptor(PR) ≥ 10%).
4. Patients who have undergone radical mastectomy and are planning to receive OFS treatment.
5. Have received (neo)adjuvant chemotherapy and radiotherapy.
6. Eastern Cooperative Oncology Group Performance Status(ECOG PS) score of 0-1.
7. Complete medical records.
8. Willing to accept long-term follow-up.
9. Any adverse events that occurred during adjuvant chemotherapy (if applicable) have recovered or decreased to grade 1 (according to CTCAE v5.0) at the start of OFS treatment.

Exclusion Criteria:

1. Simultaneously participating in another blinded clinical study.
2. Presence of other active malignant tumors or multiple primary cancers.
3. Pregnant or lactating women.
4. Other conditions that the investigator deems unsuitable for inclusion in the study.
5. Planning to use systemic therapies not described in the study cohort during the endocrine therapy phase (such as, but not limited to, chemotherapy, Antibody-Drug Conjugates(ADCs), or immunotherapy).

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Early-stage HR-positive premenopausal breast cancer patients receiving OFS treatment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adherence to different Ovarian Function Suppression (OFS) combination regimens and reasons for discontinuation.	The proportion of patients who discontinue OFS within 2 years.	Follow-up will be conducted every 3 months during the period from baseline to 2 years of endocrine therapy.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Effect of OFS Treatment Duration on Prognosis.	To observe the effect of OFS treatment duration on prognosis.	3-year iDFS rate for OFS treatment duration ≥2 years and <2 years
3-year iDFS for Different OFS Combination Regimens.	3-year iDFS for different OFS combination therapy regimens.	3 years.
Safety of different combination regimens	The collection and analysis of various adverse events and serious adverse events that occur during different treatment processes.	During the follow-up period, which is every 3 months within the first 2 years, and every 6 months from year 2 to year 3
3-year iDFS of different subgroups	The 3-year invasive disease-free survival (iDFS) for different patient subgroups.	3 years

Collaborators and Investigators

• Sponsor: Zhejiang Cancer Hospital
• Collaborators: Beijing Health Promotion Association

Study record dates

Study Major Dates

• Study Start (Estimated): October 10, 2025
• Primary Completion (Estimated): July 31, 2029
• Study Completion (Estimated): December 31, 2029

Study Registration Dates

• First Submitted: September 12, 2025
• First Submitted That Met QC Criteria: September 12, 2025
• First Posted (Estimated): September 18, 2025

Study Record Updates

• Last Update Posted (Estimated): September 18, 2025
• Last Update Submitted That Met QC Criteria: September 12, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Hormone receptor positive; OFS; Early-stage breast cancer
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: IRB-2025-977

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No