Radiotherapy and Long-term Outcomes in Early Breast Cancer With SLNB Omission

NCT07803081 | Recruiting

• 1 other identifier: 2026-07-140-001
• Study Type: observational
• Target: 500
• Locations: 1 country
• Sites: 1

Brief Summary

This prospective, multicenter observational cohort study evaluates long-term outcomes in patients with early-stage invasive breast cancer who undergo breast-conserving surgery without sentinel lymph node biopsy or other axillary surgery and subsequently receive adjuvant radiotherapy. The study will evaluate recurrence, survival, radiotherapy-related toxicities, and quality of life. Radiotherapy will be delivered according to routine clinical practice at each participating institution without protocol-mandated treatment assignment. Detailed radiotherapy characteristics, including treatment volume, technique, dose and fractionation, tumor-bed boost, and radiation dose to axillary lymph node levels I-III, will be prospectively collected to evaluate their associations with clinical outcomes.

Conditions

Breast Cancer; Early-Stage Invasive Breast Carcinoma

Keywords

Partial breast irradiation; Whole breast irradiation; Breast-conserving surgery; Sentinel lymph node biopsy omission; Radiotherapy de-escalation; Clinically node-negative breast cancer; Axillary radiation dose

Outcome Measures

Primary Outcomes (1)

• 5-Year Recurrence-Free Survival Rate

  Recurrence-free survival is defined as the time from study enrollment to the first occurrence of ipsilateral invasive breast recurrence, ipsilateral regional lymph node recurrence, distant metastasis, or breast cancer death. The 5-year recurrence-free survival rate will be estimated using the Kaplan-Meier method.

  From study enrollment to 5 years

Secondary Outcomes (10)

• 5-Year Axillary Recurrence Rate

  From study enrollment to 5 years

• 5-Year Locoregional Recurrence Rate

  From study enrollment to 5 years

• 5-Year Distant Metastasis Rate

  From study enrollment to 5 years

• 5-Year Overall Survival Rate

  From study enrollment to 5 years

• Incidence of Acute Grade 2 or Higher Radiotherapy-Related Toxicity

  From the start of radiotherapy through 90 days after completion of radiotherapy

Study Arms (1)

APROOB Cohort

Patients with early-stage invasive breast cancer who undergo breast-conserving surgery without sentinel lymph node biopsy or other axillary surgery and subsequently receive adjuvant radiotherapy according to routine clinical practice. Radiotherapy may include whole-breast or partial-breast irradiation, with treatment characteristics determined by the treating physician and participating institution.

Radiation: Adjuvant Breast Radiotherapy

Interventions

Adjuvant Breast Radiotherapy RADIATION

Adjuvant radiotherapy is delivered after breast-conserving surgery according to routine clinical practice at each participating institution. Radiotherapy may include whole-breast irradiation or partial-breast irradiation, with treatment technique, dose, fractionation, and tumor-bed boost determined by the treating physician. The study does not assign or mandate a specific radiotherapy regimen.

APROOB Cohort

Eligibility Criteria

• Age: 19 Years+
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients with histologically confirmed early-stage invasive breast cancer who have undergone breast-conserving surgery without sentinel lymph node biopsy or other axillary lymph node surgery and are scheduled to receive adjuvant radiotherapy. Eligible patients will have no evidence of distant metastasis on preoperative clinical and imaging evaluation and will be prospectively enrolled at participating institutions. Treatment decisions, including radiotherapy approach and systemic therapy, will follow routine clinical practice and will not be assigned by the study.

You may qualify if:

• Female patients aged 19 years or older with histologically confirmed invasive breast cancer
• Patients who have undergone breast-conserving surgery with curative intent
• Patients who did not undergo axillary lymph node surgery, including sentinel lymph node biopsy, at the time of breast cancer surgery
• No evidence of distant metastasis on clinical and imaging evaluation before surgery
• Planned to receive adjuvant radiotherapy after breast-conserving surgery
• Ability and willingness to provide written informed consent before study participation

You may not qualify if:

• Patients initially diagnosed with breast carcinoma in situ before surgery who did not undergo sentinel lymph node biopsy but were subsequently found to have invasive breast cancer on final surgical pathology
• Receipt of neoadjuvant systemic therapy before breast cancer surgery
• History of a malignancy other than breast cancer within 5 years before study enrollment, except adequately treated non-melanoma skin cancer or carcinoma in situ other than breast carcinoma in situ
• Recurrent breast cancer
• Bilateral breast cancer or inflammatory breast cancer
• Prior radiotherapy to the ipsilateral breast or chest region
• Patients considered by the investigator to be unsuitable for study participation or long-term follow-up

Sponsors & Collaborators

• Samsung Medical Center: lead

Study Sites (1)

Samsung Medical Center

Seoul, 05649, South Korea

RECRUITING

Biospecimen

Retention: SAMPLES WITH DNA

Archived residual breast tumor tissue, including formalin-fixed paraffin-embedded (FFPE) tissue blocks or unstained slides, may be collected from participants who provide separate consent for biospecimen research. The samples may be used for histopathologic, immunohistochemical, and molecular analyses, including DNA-based analyses.

MeSH Terms

Conditions

Breast Neoplasms

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Central Study Contacts

Haeyoung Kim

CONTACT

+82234102612; haeyoung0131.kim@samsung.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 5 Years
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: August 28, 2026
• First Posted: September 3, 2026
• Study Start: August 6, 2026
• Primary Completion (Estimated): August 5, 2036
• Study Completion (Estimated): August 5, 2036
• Last Updated: September 3, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

KR (1)