Omitting regional lymph node radiotherapy 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

This project will see if women with hormone-receptor positive, HER2-negative breast cancer who have 1–3 positive axillary nodes and a low RecurIndex can safely skip regional lymph node radiotherapy.

Quick facts

• Study type: Observational
• Enrollment: 635 (estimated)
• Ages: 18 Years to 70 Years
• Sex: Female
• Sponsor: Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University (other)
• Drugs / interventions: chemotherapy, radiation
• Locations: 1 site (Guangzhou, Guangdong)
• Trial ID: NCT07179744 on ClinicalTrials.gov

What this trial studies

This is a prospective observational study enrolling women with invasive, hormone-sensitive, HER2-negative breast cancer who have 1–3 positive axillary nodes and a low RecurIndex score. Eligible patients (age 18–70, ECOG ≤2) meeting the specified pathology criteria will not receive regional nodal radiotherapy and will be followed over time. Outcomes of interest include regional recurrence, distant recurrence, overall survival, and treatment-related side effects. The goal is to compare cancer control and toxicity in this selected low-risk group to inform whether regional radiotherapy can be omitted safely.

Who should consider this trial

Good fit: Women aged 18–70 with invasive, ER-positive/HER2-negative breast cancer, 1–3 positive axillary lymph nodes, a low RecurIndex score, ECOG 0–2, and absent or minimal lymphovascular invasion are ideal candidates.

Not a fit: Patients with HER2-positive or triple-negative disease, more than three positive nodes, high RecurIndex scores, extensive lymphovascular invasion, or other high-risk features are unlikely to benefit from omitting regional radiotherapy.

Why it matters

Potential benefit: If successful, the approach could spare selected patients from regional radiotherapy and its side effects while preserving cancer control.

How similar studies have performed: Previous trials like AMAROS and studies of sentinel-node micrometastasis suggest less aggressive nodal treatment can control disease with lower morbidity in selected patients, but omitting regional radiotherapy based on a low RecurIndex in node-positive patients is relatively novel and not yet definitively proven.

Eligibility criteria

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.

Where this trial is running

Guangzhou, Guangdong

• Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University — Guangzhou, Guangdong, China (RECRUITING)

Study contacts

• Study coordinator: Yuting Tan

Conditions: Breast Cancer