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

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.

Status
Recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05634889
Acronym
T-REX
Enrollment
1350
Registered
2022-12-02
Start date
2023-03-17
Completion date
2033-12-31
Last updated
2026-05-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Breast Cancer

Keywords

breast cancer, radiotherapy, gene expression analysis, adjuvant breast cancer treatment, regional breast cancer treatment

Brief summary

T-REX is a randomized multicenter, non-inferiority trial. Aim: To evaluate whether regional radiotherapy may safely be omitted in clinically node negative breast cancer patients with one or two sentinel node macrometastases and an estrogen receptor positive, HER2-negative tumor. Leading to an improved quality of life and reduced side effects, without worsening recurrence free survival at five years. Intervention: Patients will be randomized to locoregional radiotherapy towards the breast/chestwall and regional lymph nodes vs. to a de-escalated radiotherapy. In the intervention arm no lymph node irradiation will be given. Radiotherapy is still given to the remaining breast after breast conserving surgery, but no radiotherapy is given after mastectomy. Sample size: 1350 patients Primary end-point: Recurrence free survival at five years. Gene expression analysis: For all patients gene expression analysis for the gene signatures ARTIC, POLAR and OncotypeDX will be performed and related to risk of recurrence and benefit of adjuvant radiotherapy.

Detailed description

In this multicenter, prospective randomized trial clinically node-negative breast cancer patients with 1-2 macrometastases in their sentinel lymph node biopsy, and an estrogen receptor positive, HER2-negative tumor, will be randomly assigned to either receive adjuvant locoregional radiotherapy, or no regional radiotherapy. The main aim is to evaluate whether regional radiotherapy may safely be omitted in patients with limited lymph node metastasis and an estimated low risk of locoregional recurrence. Recurrence free survival after five years is the primary outcome, which for non-inferiority should not worsen more than 4.5 percentage units. Secondary outcomes are locoregional recurrence, regional nodal recurrence, new contralateral BC, distant recurrence free survival, overall survival, non-breast malignancies, cardiac disease, arm morbidity, and health-related quality of life. Target volumes include: Standard arm - The remaining breast/chest wall, axillary lymph node levels I-III, the supraclavicular lymph nodes (level IV), the interpectoral lymph nodes and in patients with a medial/central tumor also the internal mammary lymph nodes. Intervention arm - The remaining breast after breast conserving surgery. No radiotherapy after mastectomy

Interventions

RADIATIONDe-escalation

No regional radiotherapy. Radiotherapy is given to the remaining breast after breast conserving surgery. Chest wall radiotherapy after mastectomy only in case of wide spread multifocality.

Sponsors

Region Skane
Lead SponsorOTHER
Exact Sciences Corporation
CollaboratorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

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

Design outcomes

Primary

MeasureTime frame
Recurrence Free SurvivalFive years

Secondary

MeasureTime frameDescription
Locoregional recurrenceFive years
Regional nodal recurrenceFive years
New contralateral breast cancerFive years
Distant recurrence free survivalFive years
Overall survivalFive years
Arm morbidityFive yearsAssessed by questionnaires completed by study participants digitally or on paper between randomization and start of RT, and after 1, 3, and 5 years. The questionnaire used is the Lymphedema Functioning, Disability and Health Questionnaire (Lymph-ICF) developed by Devoogdt in 2011.
Health-related quality of lifeFive yearsAssessed by the questionnaire EORTC QLQ-C-30 completed by study participants between randomization and RT, and after 1, 3, and 5 years.

Countries

Finland, Norway, Sweden

Contacts

CONTACTSara Alkner, Associate professor
sara.alkner@med.lu.se+4646171000
CONTACTT-REX Clinical Trials Office
T_Rex.onkologi@skane.se+4646171000
PRINCIPAL_INVESTIGATORSara Alkner, Associate professor

Lunds Universitet

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: May 12, 2026