Radiotherapy Dose Adaptation Based on Tumor Biology in Patients With cN2b-N3 Breast Cancer

Study Overview
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Brief Summary
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The purpose of the study is to evaluate treatment outcomes of breast cancer with internal mammary or supraclavicular lymph node metastasis according to total radiation dose of postoperative radiation therapy differentiated by tumor response to neoadjuvant chemotherapy. The main questions it aims to answer are: 5-year disease-free survival 5-year overall survival 5-year locoregional recurrence Adverse events after radiation therapy Quality of life Participants will be assessed by multi-dimensional methods before and after radiotherapy: Disease status evaluation including physical and radiological examination Quality of life assessment with questionnaires (BREAST-Q) Adverse event assessment according to CTCAE version 5.0

Official Title
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Radiotherapy Dose Adaptation Based on Tumor Biology in Patients With cN2b-N3 Breast Cancer: Non-randomized Phase II, Prospective Single Arm Study Clinical Trial

Conditions
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Breast Cancer Stage III

Intervention / Treatment
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* Radiation: Whole breast / chest wall & regional lymph node irradiation
* Radiation: Internal mammary or supraclavicular lymph node boost


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female with age 19 or older Metastasis to internal mammary and/or supraclavicular lymph nodes, assessed by radiological exams and/or biopsy Underwent neoadjuvant chemotherapy Pathologic confirmation of invasive breast cancer treated with breast conserving surgery or mastectomy Eastern Cooperative Oncology Group performance status 0-2 Informed consent Exclusion Criteria: Previous history of radiation therapy to the chest Distant metastasis

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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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Postoperative radiation therapy to breast / chest wall and regional lymph node area<br>Patient achieved complete response after neoadjuvant chemotherapy will receive postoperative radiation therapy with dose of 42.4 Gy in 16 fractions to whole breast / chest wall and regional lymph node area. Internal mammary or supraclavicular lymph node area boost will be simultaneously delivered with total dose of 53.6 Gy in 16 fractions. Patient with partial response, stable disease, or progressive disease after neoadjuvant chemotherapy will receive postoperative radiation therapy with dose of 42.4 Gy in 16 fractions to whole breast / chest wall and regional lymph node area. Internal mammary or supraclavicular lymph node area boost will be simultaneously delivered with total dose of 56.0 Gy in 16 fractions. | Radiation: Whole breast / chest wall & regional lymph node irradiation<br>* Whole breast / chest wall and corresponding regional lymph node irradiation with dose of 42.4 Gy in 16 fractions<br>Radiation: Internal mammary or supraclavicular lymph node boost<br>* Simultaneous boost to Internal mammary or supraclavicular lymph node area with dose of total 53.6 Gy or 56.0 Gy in 16 fractions, depending on the response after neoadjuvant chemotherapy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 5-year disease-free survival | The event for disease-free survival is defined as any disease recurrence or breast cancer-related death | 5 years from the initiation of the radiation therapy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 5-year overall survival | The event for overall survival is defined as death of patient with any cause. | 5 years from the initiation of the radiation therapy | 
| 5-year locoregional recurrence | The event for locoregional recurrence is defined as disease recurrence in irradiated breast / chest wall and/or regional lymph node area including internal mammary and supraclavicular lymph node area. | 5 years from the initiation of the radiation therapy | 
| Adverse events | Adverse events after radiation therapy is graded according to CTCAE version 5.0. | 5 years from the initiation of the radiation therapy | 
| Quality of life (BREAST-Q™) | Quality of life is assessed by BREAST-Q™ questionnaires. Each score from BREAST-Q™ scales ranges from 0 to 100. Higher scores reflect a better outcome except Cancer Worry scale. | 5 years from the initiation of the radiation therapy |