Regional Radiotherapy Omission in Low-Risk Node Positive Breast Cancer

A Multicenter, Prospective, Observational Study of Regional Radiotherapy Omission in Node Positive Patients With RecurIndex Low-risk Breast Cancer

The purpose of this study is to determine whether certain patients can safely omit regional lymph node radiotherapy. These women must have hormone-sensitive, Her2-negative tumors, have 1-3 positive axillary nodes and have RecurIndex low-risk.

Study Overview

• Status: Recruiting
• Conditions: Breast Cancer
• Intervention / Treatment: Procedure: Omission of Regional Radiotherapy

• Study Type: Observational
• Enrollment (Estimated): 635

Contacts and Locations

• Study Contact: Name: Yuting Tan; Phone Number: 8615913198466; Email: tanyt3@mail.sysu.edu.cn
• Study Contact Backup: Name: Xiaobo Huang; Phone Number: 8613556080080; Email: huangxb@mail.sysu.edu.cn

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China, 510120
      • Recruiting
      • Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University
      • Contact: Yuting Tan; Phone Number: 8615913198466; Email: tanyt3@mail.sysu.edu.cn
      • Contact: Xiaobo Huang; Phone Number: 8613556080080; Email: huangxb@mail.sysu.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

pT1-2N1M0 breast cancer

Description

Inclusion Criteria:

• Age ≥ 18 years old, ≤ 70 years old.
• Eastern Cooperative Oncology Group (ECOG) ≤ 2.

• Postoperative pathology is clearly diagnosed as invasive breast cancer. Meet the clinical definition of low risk: ①Axillary lymph node micrometastasis (N1mic) or ②N1 patients who meet the following conditions at the same time,

  a）Age ≥ 40 years old, b）Vascular tumor thrombus (LVI) negative or allow few positive LVI (excluding extensive or massive LVI), c）ER positive (ER ≥ 1%) and HER2 negative (HER2 expression negative or + by IHC, or 2+ but negative by FISH).

• Postoperative pathological diagnosis of axillary lymph node status is any of the following: a. Sentinel lymph node biopsy or axillary lymph node dissection for micrometastasis (N1mic), b. Sentinel lymph node biopsy for 1-2 lymph node macrometastasis (N1sln), c. Sentinel lymph node biopsy + axillary lymph node dissection or simple axillary lymph node dissection for 1-3 lymph node metastasis (N1).
• The patient must have sufficient primary fresh frozen specimens or post- paraffin tissue sections for RecurIndex testing.
• Patients must have RecurIndex low risk obtained from testing of breast tumor tissue from a core biopsy or from the surgical specimen.
• The primary tumor and breast undergo breast-conserving surgery or total resection ± breast reconstruction (autologous/prosthetic).
• There must be adequate systemic examination (such as chest X-ray, B- ultrasound, CT, etc.) within 3 months before randomization of radiotherapy to confirm that there is no distant metastasis.
• Preoperative or radiotherapy should be performed within 12 months of randomization and must have mammography and/or MRI to confirm that there is no contralateral breast cancer.
• At least 4 courses of adjuvant chemotherapy with anthracycline or taxane should be completed after surgery.
• Radiotherapy must be performed sequentially after the completion of adjuvant chemotherapy, starting no later than 8 weeks after the end of chemotherapy.
• No previous history of malignant tumors, except for basal cell carcinoma of the skin.
• Signed an informed consent form.

Exclusion Criteria:

• Postoperative radiotherapy was confirmed as T3-4, N0, N2-3, M1 lesion staging before enrollment.
• Receive any new adjuvant therapy before surgery, including chemotherapy, endocrine therapy, targeted therapy or radiation therapy.
• Patients who underwent total mastectomy and only sentinel lymph node biopsy.
• Have a history of contralateral breast cancer.
• History of chest radiotherapy.
• combined with severe heart, lung, liver, kidney, hematopoietic, neurological diseases, and mental illness.
• History of autoimmune diseases such as scleroderma or active lupus erythematosus.
• pregnant and lactating patients.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Node Positive Breast Carcinoma; Omission of Regional Radiotherapy	Procedure: Omission of Regional Radiotherapy; Omission of Regional Radiotherapy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Local-regional recurrence rate	defined as time between randomization and the time of any recurrence of ipsilateral chest, breast, regional lymph node recurrence, distant metastases, or death occurred	5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recurrence free survival (RFS)	defined as time between randomization and the time of any recurrence of ipsilateral chest, breast, regional lymph node recurrence, distant metastases, or death occurred	5 years
Any first recurrence (AFR)	defined as any recurrence of ipsilateral chest, breast, regional lymph node recurrence, or distant metastases by Imaging or pathology	5 years
Local-regional recurrence free survival (LRFS)	defined as time between randomization and the time of any recurrence of ipsilateral chest, breast, regional lymph node recurrence, distant metastases, or death occurred	5 years
Overall Survival (OS)	defined as time between randomization and the time of death occurred	5 years
Disease free survival (DFS)	defined as time between randomization and the time of disease recur or death occur	5 years
Beast cancer specific mortality (BCSM)	defined as time between randomization and the time of death occur specific due to breast cancer	5 years
Patient life quality measurement	At the screening period and after the end of radiotherapy, each group of patients was enrolled in the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ) Cancer-30 (C30)	5 years
Patient life quality measurement	At the screening period and after the end of radiotherapy, each group of patients was enrolled in the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ) Breast-23 (BR23)	5 years

Collaborators and Investigators

• Sponsor: Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University
• Collaborators: Sun Yat-sen University

Study record dates

Study Major Dates

• Study Start (Actual): July 6, 2022
• Primary Completion (Estimated): July 6, 2027
• Study Completion (Estimated): July 5, 2032

Study Registration Dates

• First Submitted: September 13, 2022
• First Submitted That Met QC Criteria: September 16, 2025
• First Posted (Actual): September 18, 2025

Study Record Updates

• Last Update Posted (Actual): September 1, 2026
• Last Update Submitted That Met QC Criteria: August 28, 2026
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: REOM

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