A Real-World Study on the Impact of Different Adjuvant Treatment Regimens on Prognosis in Non-pCR Patients With HER2-Positive Breast Cancer After Neoadjuvant Therapy

This study is a multicenter, retrospective, real-world cohort study. It retrospectively collected data from HER2-positive breast cancer patients who received neoadjuvant therapy with trastuzumab-containing chemotherapy regimens and had Non-pCR after surgery between July 2019 and July 2025. Patients were divided into two groups based on their adjuvant treatment regimens: the trastuzumab combined with pertuzumab group (HP) and the ado-trastuzumab emtansine group (T-DM1). The planned sample size is 2000 cases.

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Key information

Conditions

Early Breast Cancer Breast Diseases Breast Neoplasms Neoplasms Neoplasms by Site Skin Diseases Skin and Connective Tissue Diseases

Age range

18 year and older

Sex eligibility

Female

Study type

Observational

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Histopathologically confirmed HER2-positive breast cancer (i.e., immunohistochemistry (IHC) staining result of 3+, or HER-2 2+ with fluorescence in situ hybridization showing HER-2 gene amplification);
Received neoadjuvant therapy with chemotherapy combined with trastuzumab before surgery: including at least 6 cycles of chemotherapy, with at least 4 cycles of taxane-based chemotherapy; and at least 4 cycles of trastuzumab treatment (including trastuzumab biosimilars and subcutaneous formulations);
Completion of radical surgery, postoperative pathology confirms the presence of invasive carcinoma in the breast and/or axillary lymph nodes after neoadjuvant therapy.
Hormone receptor status is known.

Exclusion criteria

Combine other systemic malignant tumors, excluding cured basal cell carcinoma of the skin and cervical carcinoma in situ;
Stage IV metastatic breast cancer;
Incomplete clinical pathology and follow-up data; Study endpoints

Treatment and study plan

Primary outcomes

Three-year invasive disease-free survival (iDFS) rate for non-pCR patients

Time frame: From date of enrollment until the date of first documented progression or date of death from any cause, whichever came first, assessed up to 3 years.

iDFS events include local and regional recurrence, distant metastasis, contralateral invasive breast cancer, second non-breast primary cancer (excluding non-invasive carcinoma in situ), and death from any cause at 3 years.

Secondary outcomes

3-year iDFS rate in Near-pCR patients:

Time frame: From date of enrollment until the date of first documented progression or date of death from any cause, whichever came first, assessed up to 3 years.

3-year iDFS rate in Near-pCR patients: iDFS events include local and regional recurrence, distant metastasis, contralateral invasive breast cancer, second non-breast primary cancer (excluding non-invasive carcinoma in situ), and death from any cause at 3 years in Near-pCR patients (Near-pCR is defined as Miller & Payne grade 4, MP5 with invasive cancer present in axillary lymph nodes, RCB1).
Overall survival

Time frame: It is a direct measure of the treatment's ultimate impact on patient survival.

Overall Survival (OS) refers to the length of time from either the date of diagnosis or the start of treatment for a disease (such as cancer) until death from any cause.
Adverse Events

Time frame: From date of enrollment until adjuvant therapy after surgery 1 year

Safety refers to the assessment of adverse events (AEs) and potential risks associated with a medical intervention (e.g., drug, device, procedure)

Sponsors and collaborators

Lead sponsor

Hebei Medical University Fourth Hospital

Other

Registry information

Official study title

Retrospective Real-World Cohort Study on the Impact of Different Adjuvant Treatment Regimens on Prognosis in Non-pCR Patients With HER2-Positive Breast Cancer After Neoadjuvant Therapy

Important dates

Study start: 2026
Primary completion: 2026
Study completion: 2026
First posted: Apr 20, 2026
Registry last updated: Apr 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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