Tailored Radiotherapy for Clinically Node-negative Breast Cancer Patients with 1-2 Sentinel Node Macrometastases A Multicenter Randomized Phase 3 Trial Comparing Regional Radiotherapy with De-escalated Treatment

What this Trial Is About

Researchers are evaluating whether regional radiotherapy can be safely omitted in clinically node-negative breast cancer patients who have one or two sentinel node macrometastases and an estrogen receptor positive, HER2-negative tumor. This trial aims to improve quality of life and reduce side effects without worsening recurrence free survival at five years. The study is a randomized, multicenter, non-inferiority trial with a planned enrollment of 1350 patients. Participants will be randomly assigned to receive either standard locoregional radiotherapy, which includes treatment to the remaining breast or chest wall and regional lymph nodes, or a de-escalated radiotherapy approach. In the intervention group, no lymph node irradiation is given radiotherapy is only delivered to the remaining breast after breast conserving surgery, and not after mastectomy unless there is widespread multifocality. Gene expression analyses will be performed for all patients to relate gene signatures to recurrence risk and radiotherapy benefit. During the study, patients will be monitored through regular assessments to measure recurrence free survival at five years, which is the primary outcome. Secondary outcomes include locoregional and regional nodal recurrence, new contralateral breast cancer, distant recurrence free survival, overall survival, arm morbidity, and health-related quality of life. Follow-up will continue for at least five years to evaluate these outcomes and monitor safety and quality of life changes over time.

The T-REX Trial: Tailored Regional External Beam Radiotherapy in Clinically Node-negative Breast Cancer Patients With 1-2 Sentinel Node Macrometastases.