Distribution of the Homologous Recombination-related (HRR) Genesmutationsand HRD in Breast Cancer

Landscape Ofhomologous Recombination-related (HRR) Genes Mutations and HRD, and Correlation With Survival in HER2-lowbreast Cance

This is a cross-sectional and an observational study, investigator-initiated study in HER2-low breast cancer patients. Approximately 255 subjects with HRD (homologous recombination deficiency) assessment will be enrolled in this study to examine the distribution and features of HRD/HRR (homologous recombination repair).

In this study, investigators plan to clarify the frequency of HRR/HRD in Chinese patients with HER2-low breast cancer.

In addition, it is planned to investigate any association between invasive disease-free survival (iDFS)/overall survival (OS) and HRD/HRR in HER2-low breast cancer patients.

Study Overview

• Status: Recruiting
• Conditions: Breast Cancer; HER2-low Breast Cancer
• Intervention / Treatment: Other: Standard Management

• Study Type: Observational
• Enrollment (Estimated): 255

Contacts and Locations

• Study Contact: Name: Gong Chang, doctor; Phone Number: 02034070499; Email: changgong282@163.com

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China, 510120
      • Recruiting
      • Sun Yat-sen Memorial Hospital of Sun Yat-sen University
      • Contact: Gong Chang, doctor; Phone Number: 02034070499; Email: changgong282@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Female patients aged 18-70 years with pathologically confirmed HER2-low breast cancer (defined as IHC 2+/ISH- or IHC 1+ per ASCO/CAP guidelines)

Description

Inclusion Criteria:

1. Female patients aged 18-70 years with pathologically confirmed HER2-low breast cancer (defined as IHC 2+/ISH- or IHC 1+ per ASCO/CAP guidelines);
2. ECOG performance status of 0 or 1;
3. Treatment-naïve operable primary breast cancer with completed homologous recombination deficiency (HRD) assessment;

5）Absence of distant metastasis; 6）Availability of adequate tumor tissue and blood samples for biomarker analysis.

Exclusion Criteria:

1. Recurrent or inoperable locally advanced breast cancer;
2. Bilateral breast cancer;
3. History of other malignant tumors within the past 5 years;
4. Incomplete clinical or pathological data.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Experimental ARM; All patients received standard care for postoperative management.	Other: Standard Management; Standard Management

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
1.To assess the distribution characteristics of mHRR/HRD in breast cancer with low HRE2 expression in Chinese population	the distribution and features of HRD /HRR is evaluated.	At the time of 4 weeks after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To compare the correlation between iDFS/OS and different adjuvant treatment regimens for breast cancer with low HER2 expression	IDFS, was a composite endpoint defined as the time from enrollment until the date of the first occurrence of one of the following events: Ipsilateral invasive breast cancer recurrence (same breast); Ipsilateral (same side of body) local regional invasive breast cancer recurrence (axilla, regional lymph nodes, chest wall, and/or skin); Distant recurrence (evidence of breast cancer in any anatomic site); Death attributable to any cause; Contralateral (opposite side of the body) invasive breast cancer. 3-year Overall survival (OS) was defined as time from date of randomization to death from any cause, otherwise cases were censored at date last known to be alive. Association between IDFS/OS and HRD/HRR information is evaluated.	At the time of 36 months after surgery
To assess the clinical characteristics between patients with mutations and non-mutation	Association between mutations and non-mutations group in HRD/HRR is assessed.	At the time of 4 weeks after surgery
To investigate the HRR/HRD characteristics and clinical characteristics (family history, age pathological feature es, etc.) of breast cancer patients with low HER2 expression	Association between multivariate prognostic factors and survival is evaluated.	At the time of 4 weeks after surgery

Collaborators and Investigators

• Sponsor: Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University
• Investigators: Principal Investigator: Gong Chang, doctor, Sun Yat-sen Memorial Hospital of Sun Yat-sen University

Study record dates

Study Major Dates

• Study Start (Actual): August 7, 2022
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): May 31, 2027

Study Registration Dates

• First Submitted: July 10, 2022
• First Submitted That Met QC Criteria: July 18, 2022
• First Posted (Actual): July 20, 2022

Study Record Updates

• Last Update Posted (Estimated): October 3, 2025
• Last Update Submitted That Met QC Criteria: September 29, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Homologous recombination deficiency; Homologous recombination-related
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: SYSKY-2022-030-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No