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.