De-escalation of RNI in Breast Cancer Patients With pN0 After Neoadjuvant Therapy (OMIT-RNI)

Prospective Comparative Study of Response-Adapted De-escalation of Regional Nodal Irradiation in Initially Node Positive Breast Cancer Patients With Pathological Nodal Complete Response After Neoadjuvant Therapy

Prospective Comparative Study of Response-Adapted De-escalation of Regional Nodal Irradiation in Initially Node Positive Breast Cancer Patients with Pathological Nodal Complete Response After Neoadjuvant Therapy

Study Overview

• Status: Not yet recruiting
• Conditions: Breast Cancer
• Intervention / Treatment: Radiation: Adjuvant Radiotherapy

Detailed Description

This prospective, randomized comparative study aims to evaluate the clinical outcomes and safety of response-adapted de-escalation of Regional Nodal Irradiation (RNI) in initially node-positive (cN1) breast cancer patients who achieved a pathological nodal complete response (pCR) following neoadjuvant systemic therapy. Patients will be randomized into two arms: Arm A (Experimental Arm) which omits regional nodal irradiation, and Arm B (Control Arm) which receives standard regional nodal irradiation.

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Aya A Hussein, MD candidate; Phone Number: 0 11 539109 01023423815; Email: ayaahmed@med.sohag.edu.eg

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Female patients >= 18 years old.
• Histologically confirmed invasive breast cancer, cT1-3 N1M0 according to the 8th AJCC edition.
• Biopsy-proven cN1 disease at diagnosis.
• Completion of standard neoadjuvant systemic therapy.
• Surgical treatment of breast and axilla.
• Pathologically confirmed ypN0 status.
• ECOG performance status 0-2.
• Suitable for adjuvant radiotherapy.
• Signed informed consent.

Exclusion Criteria:

• Metastatic disease (M1).
• Prior thoracic irradiation.
• Pregnancy or lactation.
• Severe uncontrolled comorbid illness.
• Any contraindication to radiotherapy.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm A: Experimental Arm; Patients will receive whole breast irradiation (WBI) following breast-conserving surgery or chest wall irradiation (CWI) following mastectomy, without regional nodal irradiation (RNI).	Radiation: Adjuvant Radiotherapy; Adjuvant radiation therapy will be delivered using Three-Dimensional Conformal Radiotherapy (3DCRT) or Intensity-Modulated Radiotherapy (IMRT). Standard institutional contouring and dosing protocols will be applied to the target volumes (whole breast or chest wall, with or without regional nodal regions) based on the randomized arm assignment.
Active Comparator: Arm B:Control Arm; Patients will receive standard whole breast irradiation (WBI) or chest wall irradiation (CWI) combined with standard regional nodal irradiation (RNI) according to institutional protocol and current international guidelines.	Radiation: Adjuvant Radiotherapy; Adjuvant radiation therapy will be delivered using Three-Dimensional Conformal Radiotherapy (3DCRT) or Intensity-Modulated Radiotherapy (IMRT). Standard institutional contouring and dosing protocols will be applied to the target volumes (whole breast or chest wall, with or without regional nodal regions) based on the randomized arm assignment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Locoregional Recurrence (LRR) Rate	The percentage of patients who experience tumor recurrence in the ipsilateral breast/chest wall or regional lymph nodes (axillary, supraclavicular, or internal mammary lymph nodes) during the follow-up period	3 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Invasive Disease-Free Survival (iDFS)	The time from randomization to the date of first documentation of invasive local, regional, or distant recurrence, contralateral invasive breast cancer, or death from any cause.	5 years
Radiation Toxicity	Incidence of acute and late radiation toxicities, including lymphedema, radiation pneumonitis, cardiac toxicity, brachial plexopathy, and shoulder dysfunction, graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.	From start of radiotherapy up to 1 year post-treatment
Overall Survival (OS)	The time from randomization to the date of death from any cause.	5 years

Collaborators and Investigators

• Sponsor: Aya Ahmed Sayed
• Investigators: Study Chair: Mohamed Soliman, Sohag University

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): June 1, 2029

Study Registration Dates

• First Submitted: July 19, 2026
• First Submitted That Met QC Criteria: July 21, 2026
• First Posted (Actual): July 24, 2026

Study Record Updates

• Last Update Posted (Actual): July 24, 2026
• Last Update Submitted That Met QC Criteria: July 21, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Regional Nodal Irradiation
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms; Therapeutics; Radiotherapy; Combined Modality Therapy; Radiotherapy, Adjuvant
• Other Study ID Numbers: Soh-Med--26-7-1MD

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared outside the study investigators.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No