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

Study Overview
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Brief Summary
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This was a cross-sectional and an observational study, investigator-initiated study in HER2-low breast cancer patients. Approximately 335 subjects will be enrolled in this study to examine the distribution and features of HRD (Homologous recombination deficiency)/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.

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

Conditions
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Breast Cancer, HER2-low Breast Cancer

Intervention / Treatment
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* Other: Standard Management


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: female patients who have pathologically documented breast cancer that: Has a history of HER2-low expression, defined as IHC 2+/ISH- or IHC 1+ (ISH- or untested) with a validated assay ASCO/CAP guidelines in the metastatic setting Femalepatients must be at least 18 years of age ECOG Performance Status of 0 or 1 patients with operable primary breast cancer who underwent radical surgery and No patients received preoperative neoadjuvant therapy. No distant metastasis occurred Patient must have adequate tumor andbloodsample for biomarker assessment Exclusion Criteria: recurrent or advanced metastatic breast cancer Bilateral breast cancer (including multifocal breast cancer. All histological lesions were HER2 1+ or 2+, not detected by FISH amplification and HR positive according to ASCO guidelines) Other malignant tumors within 5?years Clinical diagnosis and treatment information is incomplete

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental ARM<br>All patients received standard care for postoperative management. | Other: Standard Management<br>* Standard Management<br>|

What is the study measuring?
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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 18 mouths after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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 18 mouths after surgery | 
| 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 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 18 months after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Homologous recombination-related, Homologous recombination deficiency