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Tailored radiotherapy for breast cancer patients with limited lymph node involvement

The T-REX-Trial: Tailored Regional External Beam Radiotherapy in Clinically Node-negative Breast Cancer Patients With 1-2 Sentinel Node Macrometastases; an Open, Multicenter, Randomized Non-inferiority Phase 3-trial.

Not applicable Interventional Region Skane · NCT05634889

This study is testing if skipping radiation to the lymph nodes is safe for breast cancer patients with a specific type of tumor and limited lymph node involvement, to see if it helps them live longer without cancer returning.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment1350 (estimated)
Ages18 Years and up
SexAll
SponsorRegion Skane Academic / other
Locations30 sites (Helsinki and 29 other locations)
Trial IDNCT05634889 on ClinicalTrials.gov

What this trial studies

The T-REX trial is a randomized multicenter trial aimed at evaluating the safety of omitting regional radiotherapy in clinically node-negative breast cancer patients who have one or two sentinel node macrometastases and an estrogen receptor positive, HER2-negative tumor. Participants will be randomly assigned to receive either standard locoregional radiotherapy or a de-escalated approach that excludes lymph node irradiation. The primary outcome is recurrence-free survival at five years, with secondary outcomes including overall survival and health-related quality of life. Gene expression analysis will also be performed to assess tumor characteristics.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with primary unifocal or multifocal invasive breast cancer that is clinically node-negative and has limited lymph node metastasis.

Not a fit: Patients with regional or distant metastases, previous radiotherapy in the target area, or other significant health issues may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could improve the quality of life for patients by reducing unnecessary radiotherapy and its associated side effects without compromising cancer control.

How similar studies have performed: Other studies have explored de-escalation strategies in breast cancer treatment, indicating potential for success, but this specific approach is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Primary unifocal or multifocal invasive breast cancer T1-T2.
2. Clinically N0.
3. Macrometastasis (\>2mm) in 1-2 lymph nodes at sentinel node biopsy.
4. Oral and written consent.
5. Age ≥ 18 years.
6. All resection margins are tumor free (no tumor on ink).
7. Primary tumor ER-positive, HER2-negative.

Exclusion Criteria:

1. Regional or distant metastases outside the ipsilateral axilla.
2. Previous RT towards the planned target area, i.e. the ipsilateral chest/lymph nodes.
3. Neoadjuvant systemic therapy.
4. Axillary lymph node dissection or other previous axillary surgery on the affected side.
5. Prior history of invasive breast cancer.
6. Pregnancy.
7. Bilateral invasive breast cancer.
8. Contraindication for radiotherapy or systemic treatment.
9. Inability to absorb or understand the contents of the informed consent form; for example, through disability, inadequate language skills or dementia.
10. Other invasive cancer within 5 years prior to breast cancer diagnosis

Where this trial is running

Helsinki and 29 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Breast Cancerbreast cancerradiotherapygene expression analysisadjuvant breast cancer treatmentregional breast cancer treatment
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.