NCT07469267

Level I-II Axillary Irradiation in Breast Cancer With Sentinel-Node Macro-metastases

Entire Regional Nodal Irradiation vs. Level I-II Axillary Irradiation in Clinically Node-negative Breast Cancer Patients With 1-2 Sentinel Node Macro-metastases (RELAX)：A Prospective, Multicenter, Randomized, Phase 3 Clinical Trial

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 1,608 (estimated)
• Sponsor: Fudan University · Academic / Other
• Sex: Female
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The RELAX trial is an open-label, multicenter, non-inferiority, randomized, phase 3 clinical trial. Multiple randomized trials have demonstrated the safety of omitting complete axillary-lymph-node dissection in patients with invasive breast cancer and limited sentinel lymph node metastases. However, the necessity and optimal extent of regional nodal irradiation remains uncertain. The aim of this study is to evaluate whether level I-II axillary irradiation is non-inferior to whole regional nodal irradiation in terms of disease-free survival in clinically node-negative breast cancer patients with 1-2 sentinel lymph node macro-metastases.

Detailed description

PRIMARY OBJIECTIVE: To evaluate whether level I-II axillary irradiation is non-inferior to whole regional nodal irradiation in terms of disease-free survival in clinically node-negative breast cancer patients with 1-2 sentinel lymph node macro-metastases. SECONDARY OBJECTIVES: I. to estimate the difference of overall survival; II. to estimate the difference of ipsilateral regional recurrence; III. to estimate the difference of ipsilateral local regional recurrence; IV. to estimate the difference of distant recurrence; V. to estimate the difference of radiation related toxicities and quality of life. Outline: Patients are randomized in a 1:1 ratio to two treatment arms. Arm A (Level I-II axillary irradiation): Radiation is delivered to the breast after breast conserving surgery(BCS) or chest wall after mastectomy, level I-II axillary lymph nodes. Internal mammary nodes(IMN) is optional and it is recommended to irradiate IMN when the tumor is located in the medial or central quadrant. Arm B (Entire regional nodal irradiation): Radiation is delivered to the breast after BCS or chest wall after mastectomy, whole axillary lymph nodes (levels I-III) and supraclavicular lymph nodes. IMN is optional and it is recommended to irradiate IMN when the tumor is located in the medial or central quadrant.

Conditions

• Breast Cancer
• Radiotherapy

Interventions

Type	Name	Description
RADIATION	Entire regional nodal irradiation	Radiation is delivered to the breast after BCS or chest wall after mastectomy, whole axillary lymph nodes (levels I-III) and supraclavicular lymph nodes. Internal mammary nodes(IMN) is optional and it is recommended to irradiate IMN when the tumor is located in the medial or central quadrant. Both hypofractionated and conventional fractionated radiation therapy are permitted: the conventional fractionated regimen is 50 Gy in 25 fractions of 2 Gy; the hypofractionated schedule is 42.56 Gy in 16 fractions of 2.66 Gy after mastectomy, or 40.05 Gy in 15 fractions of 2.67 Gy after breast-conserving surgery. Tumor bed after breast-conserving surgery is at the discretion of the treating physician, boost doses will be 10\~16 Gy in 5\~8 fractions of 2 Gy or 10.68\~16.2 Gy in 4\~6 fractions of 2.67 Gy.
RADIATION	Level I-II axillary irradiation	Radiation is delivered to the breast after BCS or chest wall after mastectomy and low axillary lymph nodes (levels I-II). Internal mammary nodes(IMN) is optional and it is recommended to irradiate IMN when the tumor is located in the medial or central quadrant. Both hypofractionated and conventional fractionated radiation therapy are permitted: the conventional fractionated regimen is 50 Gy in 25 fractions of 2 Gy; the hypofractionated schedule is 42.56 Gy in 16 fractions of 2.66 Gy after mastectomy, or 40.05 Gy in 15 fractions of 2.67 Gy after breast-conserving surgery. Tumor bed after breast-conserving surgery is at the discretion of the treating physician, boost doses will be 10\~16 Gy in 5\~8 fractions of 2 Gy or 10.68\~16.2 Gy in 4\~6 fractions of 2.67 Gy.

Timeline

• Start date: 2025-10-24
• Primary completion: 2032-12-31
• Completion: 2035-12-31
• First posted: 2026-03-13
• Last updated: 2026-03-13

Locations

15 sites across 1 country: China