Preoperative Partial Breast Reirradiation and Repeat Breast-conserving Surgery in Patients With Recurrent Breast Cancer: the REPEAT Trial (REPEAT)

July 14, 2026 updated by: Desiree H.J.G.D. van den Bongard, MD Ph, Amsterdam UMC, location VUmc

Preoperative Partial Breast Reirradiation and Repeat Breast-conserving Surgery in Patients With Recurrent Breast Cancer: the REPEAT Trial - a Study Protocol

Over the past decades, interest in second breast-conserving therapy (BCT) has increased due to, among others, advancements in radiotherapy techniques. Preoperative partial breast irradiation (PBI) is an experimental treatment for patients with low-risk primary breast cancer. This approach can downstage the tumor, and may possibly reduce toxicity and improve cosmetic outcomes compared to postoperative radiotherapy. This study aims to evaluate the feasibility of single-dose preoperative PBI and second breast-conserving surgery (BCS) for patients with an ipsilateral recurrent breast event (IRBE) after previous BCT.

The REPEAT trial is a multicenter, prospective, single-arm trial investigating ablative single-dose preoperative PBI in patients with an IRBE. Eligible patients are ≥ 50 years, have a unifocal non-lobular invasive breast cancer ≤ 2 cm, Bloom-Richardson grade 1 or 2, estrogen receptor-positive, HER2-negative and clinically negative axillary lymph nodes. The study plans to enroll 25 patients. Radiotherapy planning will involve the use of CT and MRI in the treatment position. Single-dose PBI of 20 Gy to the tumor and 15 Gy to the surrounding 2 cm of breast tissue will be delivered using a conventional or MR-guided linear accelerator. Tumor response will be monitored preoperatively using MRI and liquid biopsies to identify biomarkers for evaluating radiosensitivity. BCS will be performed 3 weeks post-PBI. The primary endpoint is the incidence of grade 2 or higher treatment-associated acute toxicity within 90 days. Secondary endpoints include the evaluation of acute (grade 1) and late toxicity, radiologic and pathologic response, mastectomy rate, patient-reported outcomes, cosmetic outcome, local, regional and distant recurrence rates, survival outcome, and biomarkers in liquid biopsies and tumor tissue. Patients will be followed up to 5 years after PBI.

This trial will evaluate the feasibility of single-dose preoperative PBI and BCS for patients with IRBE. This treatment approach is expected to minimize the irradiated volume, reduce toxicity, and improve cosmetic outcomes compared to postoperative PBI after second BCS. Identifying biomarkers for radiosensitivity will help in selection patients and tailoring treatment.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

25

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Netherlands
      • Amsterdam, Netherlands
        • Recruiting
        • Amsterdam UMC / VU Medical Centre
        • Contact:
        • Principal Investigator:
          • Desiree HJGD Dr. van den Bongard, Dr.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  • WHO performance scale ≤ 2
  • Females at least 50 years of age with an ipsilateral invasive breast cancer event or DCIS (i.e. recurrence, second primary) after previous breast conserving surgery and radiotherapy (for invasive breast cancer/carcinoma in situ)
  • Tumor characteristics: - - Tumor size ≤ 2 cm, unifocal on MRI

On tumor biopsy:

  • Bloom-Richardson grade 1 or 2,
  • non-lobular invasive histological type carcinoma,
  • accompanying (non-extensive) DCIS is accepted within the tumor size of 2 cm on mammography and/or tumor biopsy, including no non-mass enhancement on MRI,
  • ER-positive and HER2-negative tumor,

  • No lymphovascular invasion.

    • Clinical node negative on PET-CT, ultrasound and MRI
    • No distant metastases
    • Repeat breast-conserving surgery is feasible, if no or mild late toxicity (no grade 2 or higher) from previous breast-conserving therapy
    • Adequate communication and understanding skills of the Dutch language
    • Written informed consent

Exclusion criteria:

  • Ipsilateral invasive breast cancer recurrence less than 2 years after first breast conserving therapy for breast cancer or ductal carcinoma in situ
  • Legal incapacity
  • Known breast cancer mutation gene carrier
  • Previous ipsilateral mastectomy
  • Collagen synthesis disease (e.g. Osteogeneis imperfecta, Ehlers-Danlos syndrome, systemic lupus erythematosus)
  • Invasive lobular carcinoma
  • MRI absolute contraindications as defined by the Department of Radiology
  • Indication for treatment with neoadjuvant chemotherapy
  • Non-feasible dosimetric RT plan
  • Breast implants

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: ablative single-dose PBI followed by BCS after three weeks
Eligible patients with a low-risk ipsilateral recurrent breast cancer previously treated with breast-conserving surgery and postoperative radiotherapy, will be treated with re-irradiation (i.e. ablative single-dose PBI) followed by second BCS after three weeks.
Radiation: ablative single-dose PBI
ablative single-dose PBI followed by BCS after three weeks At baseline (prior to RT) and prior to BCS, toxicity, PROMS and cosmetic outcome will be assessed. Additionally, a preoperative MRI will be performed three weeks following RT to evaluate the acute tumor response.
Other Names:
  • baseline (prior to RT) and prior to BCS, toxicity, PROMS and cosmetic outcome will be assessed.
  • a preoperative MRI will be performed three weeks following RT to evaluate the acute tumor response

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Acute toxicity
Time Frame: 90 days
The incidence of grade 2 or higher treatment-associated acute toxicity within 90 days
90 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Toxicity
Time Frame: 3,6,12 weeks and 1,2,3,4,5 years
Assessment of treatment-induced toxicity
3,6,12 weeks and 1,2,3,4,5 years
response
Time Frame: 3,6,12 weeks and 1,2,3,4,5 years
Assessment of radiologic and pathologic response, mastectomy rate
3,6,12 weeks and 1,2,3,4,5 years
PROMS
Time Frame: 3,6,12 weeks and 1,2,3,4,5 years
Assessment of PROMs
3,6,12 weeks and 1,2,3,4,5 years
cosmetic results
Time Frame: 3,6,12 weeks and 1,2,3,4,5 years
Assessment of cosmetic results
3,6,12 weeks and 1,2,3,4,5 years
oncological outcomes
Time Frame: 1,2,3,4,5 years
Assessment of oncological outcomes
1,2,3,4,5 years
immune response
Time Frame: 3,6,12 weeks and 1,2,3,4,5 years
Assessment of RT-associated immune response and biomarkers in blood and tumor tissue
3,6,12 weeks and 1,2,3,4,5 years
patient comfort during RT treatment delivery
Time Frame: during RT treatment
Assessment of patient comfort during RT treatment delivery
during RT treatment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Amsterdam UMC, location VUmc

Investigators

  • Principal Investigator: Desiree HJG van den Bongard, MD PhD, Amsterdam UMC

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2025

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

October 8, 2024

First Submitted That Met QC Criteria

October 11, 2024

First Posted (Actual)

October 15, 2024

Study Record Updates

Last Update Posted (Actual)

July 16, 2026

Last Update Submitted That Met QC Criteria

July 14, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NL85983.018.24

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Subscribe