NAUTILUS-04: No Axillary Surgical Treatment in Low-Risk Clinically Node-Negative Breast Cancer Without Whole-Breast Radiotherapy (NAUTILUS-04)

October 4, 2026 updated by: Wonshik Han

A Multicenter Randomized Controlled Non-Inferiority Trial of No Axillary Surgical Treatment in Low-Risk Clinically Node-Negative Breast Cancer Without Whole-Breast Radiotherapy

The safety of omitting sentinel lymph node biopsy (SLNB) has been established only in patients undergoing breast-conserving surgery with whole-breast radiotherapy, as demonstrated in the prior randomized trials. Whether SLNB can be omitted in patients who will not receive whole-breast radiotherapy remains unknown, despite the parallel expansion of radiotherapy de-escalation in low-risk populations.

NAUTILUS-04 is a prospective, multicenter, randomized, phase III non-inferiority trial evaluating the oncologic safety of SLNB omission in postmenopausal patients with low-risk, clinically node-negative breast cancer who are not planned to receive whole-breast radiotherapy.

Eligible patients are postmenopausal women aged 55 years or older with estrogen receptor-positive, HER2-negative invasive breast cancer, clinical T1-2 and clinically node-negative disease confirmed by physical examination and axillary ultrasound, without neoadjuvant systemic therapy. Patients must be planned for one of three local treatments: breast-conserving surgery without radiotherapy, breast-conserving surgery with accelerated partial breast irradiation, or mastectomy without radiotherapy.

A total of 1,520 patients will be randomized 1:1 to SLNB or no axillary surgery, stratified by planned breast surgery (breast-conserving surgery versus mastectomy) and age (55-64 versus 65 years or older). The primary endpoint is 5-year invasive disease-free survival. Secondary endpoints include 5-year axillary recurrence-free survival, distant recurrence-free survival, overall survival, and quality of life assessed by the EORTC QLQ questionnaire.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

1520

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Wonshik Han, Professor
  • Phone Number: 82-2-2072-0706
  • Email: hanw@snu.ac.kr

Study Locations

  • South Korea
      • Seoul, South Korea, 03080
        • Seoul National University Hospital
        • Contact:
          • Wonshik Han, Professor
          • Phone Number: 82-2-2072-0706
          • Email: hanw@snu.ac.kr

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

55 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Postmenopausal women aged 55 years or older
  • Histologically confirmed invasive breast cancer
  • Estrogen receptor-positive and HER2-negative
  • Clinical T1-2
  • Clinically node-negative by physical examination and axillary ultrasound
  • No neoadjuvant systemic therapy
  • Not planned to receive whole-breast radiotherapy
  • Planned for one of the following local treatments:
  • Cohort 1: Breast-conserving surgery without radiotherapy
  • Age under 65 years with clinical T1 tumor and biologically low risk, defined as Oncotype DX Recurrence Score 18 or less, OncoFREE Decision Index 15 or less, or Ki-67 13.25% or less with histologic grade 1 or 2
  • Age 65 years or older with clinical tumor size 3 cm or less and histologic grade 1 or 2
  • Cohort 2: Breast-conserving surgery with accelerated partial breast irradiation, with clinical T1 tumor and histologic grade 1 or 2
  • Cohort 3: Mastectomy without radiotherapy, with histologic grade 1 or 2
  • Written informed consent

Exclusion Criteria:

  • Clinically or radiologically suspicious axillary lymph nodes
  • Prior ipsilateral invasive breast cancer or prior axillary surgery
  • Bilateral breast cancer
  • Inflammatory breast cancer
  • Pregnancy
  • Any condition that precludes protocol-specified surgery or follow-up
  • Concurrent participation in another interventional clinical trial that may affect the primary endpoint of this study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: SLN omission group

No axillary surgery
Procedure: Omission of axillary surgery

Planned breast surgery is performed without any axillary surgical procedure. Neither sentinel lymph node biopsy nor axillary lymph node dissection is performed. Adjuvant treatment decisions are made without pathologic nodal information
Active Comparator: SLN group

Sentinel lymph node biopsy
Procedure: Sentinel lymph node biopsy

Sentinel lymph node biopsy is performed at the time of planned breast surgery. Subsequent axillary management and adjuvant treatment decisions follow institutional standard practice based on the pathologic nodal findings.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Invasive disease free survival
Time Frame: 5 years after randomization

Invasive disease-free survival is defined as the time from randomization to the first occurrence of invasive ipsilateral breast tumor recurrence, local or regional invasive recurrence, distant recurrence, contralateral invasive breast cancer, second primary invasive cancer, or death from any cause, according to the STEEP criteria.
5 years after randomization

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall survival
Time Frame: 5 years from randomization

Description: Overall survival is defined as the time from randomization to death from any cause.
5 years from randomization
Distant disease-free survival
Time Frame: 5 years from randomization

Distant disease-free survival is defined as the time from randomization to the first occurrence of distant recurrence or death from any cause, according to the STEEP criteria.
5 years from randomization
Axillary recurrence
Time Frame: 5 years from randomization

Axillary recurrence is defined as histologically or cytologically confirmed recurrence in the ipsilateral axillary lymph nodes, occurring as a first event or concurrently with other recurrence sites.
5 years from randomization
Health-related quality of life
Time Frame: Before surgery, and 1 and 2 years after surgery

Health-related quality of life assessed by the EORTC QLQ-C30 and EORTC QLQ-BR23 questionnaires. Scores are linearly transformed to a 0-100 scale. Higher scores on functional scales indicate better functioning, whereas higher scores on symptom scales indicate greater symptom burden.
Before surgery, and 1 and 2 years after surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Wonshik Han

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

October 1, 2034

Study Completion (Estimated)

October 1, 2034

Study Registration Dates

First Submitted

September 19, 2026

First Submitted That Met QC Criteria

September 19, 2026

First Posted (Actual)

September 25, 2026

Study Record Updates

Last Update Posted (Actual)

October 8, 2026

Last Update Submitted That Met QC Criteria

October 4, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NAUTILUS-04

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Sharing Time Frame

Beginning 12 months after publication of the primary results, ending 3 years thereafter

IPD Sharing Access Criteria

Requests should be directed to the principal investigator. Proposals will be reviewed by the study steering committee. Data will be shared after approval of the proposal and completion of a data access agreement.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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