Prospective Cohort for Tumor Bed Boost Radiotherapy in HER2 Positive Breast Cancer

Study Overview
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Brief Summary
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The purpose of this study is to analyze treatment outcomes related to tumor bed boost of postoperative radiation therapy in patient with HER2+ breast cancer who underwent breast conserving surgery. The main questions it aims to answer are: 7-year ipsilateral breast tumor recurrence 7-year disease-free survival 7-year locoregional recurrence 7-year overall survival Adverse events of radiation therapy Participants will be assessed by multi-dimensional methods after radiation therapy: Assessment for the disease status (disease-free or recurrence) including physical and radiologic examination Assessment for the adverse events according to CTCAE version 5.0

Official Title
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Prospective Cohort for Tumor Bed Boost Radiotherapy in HER2 Positive Breast Cancer

Conditions
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Breast Cancer

Intervention / Treatment
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* Radiation: Whole breast irradiation +/- tumor bed boost


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female patients with age minimum 19 Pathological confirmation of HER2+ invasive breast cancer Eastern Cooperative Oncology Group performance status 0-2 Informed consent of the participant Exclusion Criteria: Pathological confirmation of ductal carcinoma in situ of the breast Previous history of radiation therapy to ipsilateral breast

Ages Eligible for Study
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Minimum Age: 19 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

| Intervention/Treatment |
| --- |
|Radiation: Whole breast irradiation +/- tumor bed boost|Postoperative whole breast irradiation (3D-conformal radiation therapy or IMRT) with or without tumor bed boost (sequential or simultaneous integrated boost)|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ipsilateral breast tumor recurrence | The event for ipsilateral breast tumor recurrence (IBTR) was defined as any breast tumor recurrence in irradiated breast. | 7 years from the start of the postoperative radiation therapy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Disease-free survival | The event for disease-free survival (DFS) was defined as any local, regional, or distant recurrence or breast cancer-related death. | 7 years from the start of the postoperative radiation therapy | 
| Locoregional recurrence | The event for locoregional recurrence was defined as recurrence in irradiated breast / chest wall or regional lymph node area. | 7 years from the start of the postoperative radiation therapy | 
| Overall survival | The event for overall survival (OS) was defined as death of any cause. | 7 years from the start of the postoperative radiation therapy | 
| Adverse events | Adverse events were evaluated and graded according to CTCAE version 5.0. | 7 years from the start of the postoperative radiation therapy |