The Postoperative Radiotherapy in N1 Breast Cancer Patients

Study Overview
=================
Brief Summary
-----------------
This study is a multicenter, randomized, phase 3 clinical trial in patients with breast cancer, randomizing radiotherapy group (postmastectomy radiation therapy (PMRT)/whole breast irradiation plus regional radiotherapy (WBI+regional RT) versus and no PMRT/WBI alone group. This is a non-inferiority study aiming that there is no significant difference in the 7-year disease-free survival rate between the two groups.

Detailed Description
-----------------
1:1 randomization to the control group and experimental group, stratified by the type of surgery (breast-conserving surgery (BCS) versus mastectomy) and the type of histologic type (triple negative breast cancer (TNBC) versus non-TNBC) The control group: If patients received BCS, WBI+Regional RT If patients received mastectomy, PMRT The experimental group: If patients received breast conserving surgery, WBI alone If patients received mastectomy, No PMRT

Official Title
-----------------
The Postoperative Radiotherapy After Breast Conserving Surgery or Mastectomy in N1 Breast Cancer Patients: A Prospective, Multicenter, Phase III Clinical Trial

Conditions
-----------------
Radiotherapy, Breast Cancer

Intervention / Treatment
-----------------
* Radiation: No PMRT for mastectomy / No regional RT for BCS
* Radiation: PMRT for mastectomy / WBI + Regional RT for BCS


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients aged 19 years or older. A female patient who underwent breast-conserving surgery or mastectomy for invasive breast cancer. Patient with stage pN1 after surgery on histopathologic examination. However, if mastectomy was performed, 5 or more nodes should be resected in the case of 1 positive node, and axillary lymph node dissection (ALND) should be performed in case of 2 or 3 positive nodes. Patients undergoing or planning to undergo hormone therapy in the case of hormone receptor positive. Patients who have received or are expected to undergo targeted therapy in the case of human epidermal growth factor receptor(HER)-2 positive. Patients with Eastern Cooperative Oncology Group (ECOG) Scale 0-2. Patients who agreed to participate in the study. Exclusion Criteria: Patients who have received prior [neoadjuvant] chemotherapy. Patients receiving radiation therapy for salvage or palliative purposes. Patients with stage T4. Patients with ipsilateral supraclavicular and internal mammary lymph node metastases or distant metastases. Male breast cancer patient. Patients who have previously received radiation therapy to the ipsilateral breast or supraclavicular region. Patients having a history of cancer other than thyroid cancer, cervical carcinoma in situ, or skin cancer. Patients diagnosed with ductal breast carcinoma in situ, lobular carcinoma in situ, phyllodes, metaplastic cancer, or benign tumors based on histological diagnosis.

Ages Eligible for Study
-----------------
Minimum Age: 19 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: The Control group<br>If patients received mastectomy, post-mastectomy radiation therapy (PMRT) should be performed. If patients received breast conserving surgery (BCS), whole breast irradiation (WBI) + Regional radiotherapy (RT) should be performed. | Radiation: PMRT for mastectomy / WBI + Regional RT for BCS<br>* Regional RT includes high-tangent field, and can include undissected axilla. The definition of high-tangent is that the upper margin of the radiotherapy field located within 2 cm of the humeral head to include axillary levels I and II. Both hypofractionated and conventionally fractionated radiation therapy are allowed, and 3-dimensional or intensity modulated radiotherapy are allowed. The electron beam can also be used.<br>|
| Experimental: The Experimental group<br>If patients received mastectomy, No PMRT should be performed. If patients received BCS, WBI alone should be performed. | Radiation: No PMRT for mastectomy / No regional RT for BCS<br>* Regional RT includes high-tangent field, and can include undissected axilla. The definition of high-tangent is that the upper margin of the radiotherapy field located within 2 cm of the humeral head to include axillary levels I and II. Both hypofractionated and conventionally fractionated radiation therapy are allowed, and 3-dimensional or intensity modulated radiotherapy are allowed. The electron beam can also be used.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Disease-Free Survival | Time from randomization to local recurrence, regional recurrence, distant metastases, or breast cancer-related death. | 7-Year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Locoregional-Recurrence Free Survival | Time from randomization to recurrence of tumors in the ipsilateral chest wall, breast or regional lymph nodes (ipsilateral axillary/internal mammary/supraclavicular lymph nodes) or breast cancer-related death. ** Recurrence should be confirmed by histological diagnosis, but local recurrence can be diagnosed by clinical examination only when regional/remote or distant metastases already exist. | 7-Year | 
| Distant Metastases Free Survival | Time from randomization to the development of distant metastases or breast cancer-related death. | 7-Year | 
| Overall Survival | Time from randomization to the death due to any cause. | 7-Year | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Breast Cancer, Radiotherapy, Omission, Breast Conserving Surgery, Mastectomy, TNM pathologic stage N1