1-Week Versus 3-Week PBI

September 22, 2026 updated by: Jinli Ma, Fudan University

1-Week Versus 3-Week Partial Breast Irradiation Using Intensity-Modulated Radiation Therapy (IMRT) Following Breast-Conserving Surgery in Clinically Low-Risk Breast Cancer: a Phase III, Randomized Trial

This non-inferiority, phase 3 clinical trial evaluates the cosmetic non-inferiority of a one-week regimen (26 Gy/5 Fx) versus a three-week regimen (40 Gy/15 Fx) using intensity-modulated radiation therapy (IMRT) for partial breast irradiation (PBI) in low-risk breast cancer patients post-breast-conserving surgery.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

818

Phase

  • Not Applicable

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

  • China
      • Shanghai, China
        • Recruiting
        • Fudan University Shanghai Cancer Center
        • Contact:

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

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Female patients with an estimated life expectancy greater than 5 years. Meets criteria for either primary invasive breast cancer or pure ductal carcinoma in situ (DCIS).
  • For invasive breast cancer: Age 40-75 years; Underwent breast-conserving surgery with sentinel lymph node biopsy or axillary lymph node dissection; pT ≤ 3 cm (unicentric/unifocal or total multifocal size ≤ 3 cm); favorable histology (invasive ductal, mucinous, tubular, or solid papillary carcinoma, DCIS component permitted); ER+ and/or PR+; pN0(i- or i+); M0; surgical margins ≥ 2 mm.
  • For pure DCIS: Age 18-75 years; Underwent breast-conserving surgery with or without sentinel lymph node biopsy; low-to-intermediate nuclear grade; tumor size ≤ 2.5 cm; surgical margins ≥ 3 mm.
  • Presence of surgical clips or distinct postoperative seroma/tissue changes in the tumor bed allowing precise target delineation.
  • ECOG performance status 0 or 1.
  • Eligible for systemic therapy, without prior neoadjuvant systemic therapy.
  • Able to tolerate radiotherapy procedures and position immobilization.
  • No contraindications to radiotherapy.
  • Written informed consent provided.

Exclusion Criteria:

  • Unfavorable histological subtypes (e.g., invasive lobular carcinoma, invasive micropapillary carcinoma).
  • Positive axillary, internal mammary, or supraclavicular lymph nodes.
  • Presence of distant metastasis.
  • Paget's disease of the nipple.
  • History of prior ipsilateral or contralateral invasive breast cancer or DCIS.
  • Bilateral breast cancer.
  • Known germline BRCA1 or BRCA2 mutation.
  • Prior radiotherapy to the ipsilateral breast, chest wall, or regional lymph nodes.
  • Active or prior second malignancy (except adequately treated non-melanoma skin cancer).
  • Severe non-malignant comorbidities (e.g., cardiovascular disease, pulmonary disease, systemic lupus erythematosus, or scleroderma) precluding definitive radiotherapy.
  • Pregnant or lactating patients.
  • Inability or unwillingness to comply with scheduled follow-up visits.

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: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: arm 1

26Gy/5F
Radiation: 1-week PBI

26Gy/5Fx/1w, 5.2Gy/Fx, once daily
Active Comparator: arm 2

40.05Gy/15F
Radiation: 3-week PBI

40.05Gy/15Fx/3w, 2.67Gy/Fx, once daily

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Adverse cosmesis
Time Frame: 3 years

Adverse cosmetic outcome (defined as 'Fair' or 'Poor') was evaluated by an independent panel using standard photographic assessment based on the EORTC Cosmetic Rating System.
3 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall survival
Time Frame: 5 years

Overall survival is the time from randomization to death from any cause.
5 years
Rate of locoregional recurrence
Time Frame: 5 years

Locoregional recurrence is defined as the first documented recurrence in the ipsilateral breast or regional nodes.
5 years

Collaborators and Investigators

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

Sponsor

Fudan University

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 (Estimated)

October 1, 2026

Primary Completion (Estimated)

October 1, 2032

Study Completion (Estimated)

October 1, 2034

Study Registration Dates

First Submitted

September 16, 2026

First Submitted That Met QC Criteria

September 16, 2026

First Posted (Actual)

September 21, 2026

Study Record Updates

Last Update Posted (Actual)

September 25, 2026

Last Update Submitted That Met QC Criteria

September 22, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FDRT-BC-PBI

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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.

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