Partial Breast Irradiation Without Sentinel Lymph Node Biopsy in Low-Risk Early Breast Cancer

NCT07757958 · tracked via the Priya Life Science South Korea tracker

Sponsor

Samsung Medical Center

Phase

Phase 3

Started

2026-08-01

Last updated

2026-08-11

Condition(s) studied

Breast CancerNode-negative Breast CancerEarly-Stage Invasive Breast Carcinoma

Investigational drug(s) / intervention(s)

Whole Breast IrradiationPartial Breast Irradiation

Whole Breast Irradiation: Total dose 26-45 Gy in 5-20 fractions; each institution applies a pre-selected fractionation schedule consistently. CTV defined per ESTRO guideline to include the whole breast parenchyma; PTV with institutional set-up margin (e.g., 5-7 mm). Tumor bed boost (sequential 10-16 Gy in 4-8 fractions, or simultaneous integrated boost \[SIB\]) per institutional standard. Regional nodal irradiation and high-tangent technique not permitted; axillary levels I-III contoured for dosimetric analysis only.

Partial Breast Irradiation: Total dose 30-40 Gy in 5-15 fractions. Recommended schedules: 30 Gy in 5 fractions (once daily \[QD\] or twice daily \[BID\]); or 40.05 Gy in 15 fractions (QD over \~3 weeks). Axillary levels I-III contoured for incidental dosimetric analysis only (not a treatment target).

Study summary

This is a multicenter, randomized, phase III non-inferiority trial in women aged 40 years or older with clinically node-negative (cN0), pathologically pT1 (≤2 cm), grade 1-2, lymphovascular invasion (LVI)-negative invasive breast cancer treated with breast-conserving surgery (BCS) in whom sentinel lymph node biopsy (SLNB) was omitted (pNx). Eligible patients are randomized 1:1 to partial breast irradiation (PBI) or whole breast irradiation (WBI). The primary aim is to determine whether PBI is non-inferior to WBI with respect to the 5-year recurrence-free survival (RFS) rate. Secondary aims include comparison of axillary recurrence, overall survival, locoregional recurrence, treatment-related toxicity, and quality of life between arms.

Eligibility

Sex

FEMALE

Min age

40 Years

Max age

—

Healthy volunteers

Inclusion Criteria: * Female ≥40 years with histologically confirmed unilateral invasive breast cancer. * No suspicious nodal metastasis on preoperative axillary ultrasound (cN0). * Single lesion in the affected breast on preoperative breast ultrasound and mammography. * Treated with breast-conserving surgery with pathologically negative margins for the invasive tumor. * Sentinel lymph node biopsy not performed at surgery (pNx). * Maximum diameter of invasive tumor ≤2 cm on final pathology (pT1). * Histologic grade 1 or 2. * Signed informed consent prior to enrollment. Exclusion Criteria: * History of malignancy other than breast cancer within 5 years (except adequately treated non-melanoma skin cancer, or carcinoma in situ excluding breast carcinoma in situ). * Preoperative diagnosis of carcinoma in situ without axillary nodal sampling, subsequently diagnosed as invasive breast cancer on final pathology with SLNB omitted. * Lymphovascular invasion present (LVI+). * Multifocal or multicentric tumor in the same breast confirmed radiologically or pathologically. * Bilateral or inflammatory breast cancer. * Prior radiotherapy to the breast or thorax. * Confirmed pathogenic or likely pathogenic variant in a hereditary breast cancer gene (including BRCA1/2). * Recurrent breast cancer.

Primary outcome measure(s)

5-Year Recurrence-Free Survival Rate — 5 years from randomization
Proportion of patients free from a first RFS event at 5 years. An RFS event is defined as the first occurrence of ipsilateral invasive breast recurrence, ipsilateral regional nodal recurrence (including axillary), distant metastasis, or breast cancer death. Measured from date of randomization to first event.

Trial sites (1)

Facility	City	Region	Status
Samsung Medical Center	Seoul	South Korea

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Official registry record

This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.

View NCT07757958 on ClinicalTrials.gov ↗ ← All trials in South Korea