Ultra-hypofractionated Irradiation of the Whole Breast (WBI) Compared to Partial Breast Irradiation (PBI)

September 27, 2026 updated by: Marko Bojovic, Oncology Institute of Vojvodina

Ultra-hypofractionated Radiotherapy for Whole Breast Irradiation (WBI) Compared to Partial Breast Irradiation (PBI): A Single-Institution Prospective Phase 2 Trial

Female patients undergoing surgical treatment for early breast cancer and meeting the inclusion criteria for adjuvant breast radiotherapy were randomized into two groups. One group will receive adjuvant whole-breast radiotherapy in ultra-hypofractionated regimen of 26 Gy in 5 fractions. In contrast, the other group will receive partial breast irradiation with a dose of 26Gy in 5 fractions.

The study's objective is to compare the effects of both breast radiotherapy protocols in terms of locoregional disease control and survival and to compare the adverse effects of radiotherapy between the two protocols. To determine if there is a correlation between different parameters and the efficacy and degree of toxicity for both protocols.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Radiation therapy should ideally start 6-8 weeks after breast-conserving surgery but no later than 12 weeks after the surgery.

If adjuvant chemotherapy has been administered, it is recommended to start radiation therapy three weeks after chemotherapy (optionally, it can be completed before beginning chemotherapy).

The radiation therapy procedure follows the existing clinical protocol for breast radiotherapy. For radiation therapy planning, the patient is positioned supine using immobilization devices (such as a wing board or similar) to ensure daily reproducibility within a range of 5 mm. The clinical target volume (CTV) is delineated according to the recommendations of the Danish Breast Cancer Cooperative Group (DBCG) and the European Society for Radiotherapy and Oncology (ESTRO).

A total dose of 26Gy in 5 fractions every working day using the Volumetric Modulated Arc Therapy (VMAT) technique. Daily portal images are obtained, and a breathing control protocol is applied based on clinical assessment.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
106

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Locations

  • Serbia
    • Vojvodina
      • Novi Sad, Vojvodina, Serbia, 21204
        • Oncology Institute of Vojvodina

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

50 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Breast-conserving surgery
  • Invasive ductal carcinoma
  • Age ≥ 50
  • Tumor size ≤ 3 cm
  • R0 resection
  • Unicentric/unifocal carcinoma or multifocal carcinoma within 2 cm of the primary neoplasm
  • pN0 (sentinel lymph node biopsy or axillary lymph node dissection performed), N1mi
  • Hormone receptor status - any
  • Histological grade G1 or G2

Exclusion Criteria:

  • Neoadjuvant systemic therapy
  • TNBC (triple-negative breast cancer)
  • Extensive intraductal component (EIC)
  • Lymphovascular invasion (LVI)
  • associated DCIS > 2.5 cm in size or high nuclear grade

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Partial Breast Irradiation
Radiation: Partial Breast Irradiation

The course of radiotherapy with 26Gy in 5 fractions will be administered to the part of the breast where the tumor was located.
Experimental: Whole Breast Irradiation
Radiation: Ultra-hypofractionated WBI

An ultra-short course of radiotherapy with 26Gy in 5 fractions will be administered to the whole breast where the tumor was located.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Acute Radiation Toxicity
Time Frame: From the start of radiotherapy up to 6 months.

Proportion of participants experiencing acute radiation toxicity, defined as toxicity occurring within 6 months of the start of radiotherapy, graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Toxicity types assessed include gastrointestinal, genitourinary, and skin toxicity.
From the start of radiotherapy up to 6 months.
Late Radiation Toxicity
Time Frame: From 6 months after the start of radiotherapy up to 60 months.

Proportion of participants experiencing late radiation toxicity, defined as toxicity occurring more than 6 months after the start of radiotherapy, graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Toxicity types assessed include gastrointestinal, genitourinary, and skin toxicity.
From 6 months after the start of radiotherapy up to 60 months.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Time to Local-Regional Recurrence
Time Frame: From adjuvant radiotherapy until locoregional recurrence, assessed up to 10 years.

Time from adjuvant radiotherapy to the first occurrence of pathologically confirmed locoregional tumor recurrence, defined as any newly suspicious skin change(s) or palpable lymph node(s) in the irradiated area. Participants without locoregional recurrence are censored at the date of last follow-up.
From adjuvant radiotherapy until locoregional recurrence, assessed up to 10 years.
Disease-Free Survival (DFS)
Time Frame: From adjuvant radiotherapy until disease recurrence, second primary tumor, or death from any cause, assessed up to 10 years.

Time from adjuvant radiotherapy to the first occurrence of clinically confirmed local recurrence, distant metastasis, second primary tumor, or death from any cause, whichever occurs first. Participants who are alive and disease-free at the time of analysis are censored at the date of last follow-up.
From adjuvant radiotherapy until disease recurrence, second primary tumor, or death from any cause, assessed up to 10 years.
Overall Survival (OS)
Time Frame: From adjuvant radiotherapy until death from any cause, assessed up to 10 years.

Time from adjuvant radiotherapy to death from any cause. Participants who are alive at the time of analysis are censored at the date of last follow-up.
From adjuvant radiotherapy until death from any cause, assessed up to 10 years.
Time to Distant Metastasis
Time Frame: From adjuvant radiotherapy until distant metastasis or death, assessed up to 10 years.

Time from adjuvant radiotherapy to the first occurrence of distant metastasis, confirmed by imaging or pathology. Participants without distant metastasis are censored at the date of last follow-up or death.
From adjuvant radiotherapy until distant metastasis or death, assessed up to 10 years.
Physician-reported Harvard Breast Cosmesis Scale
Time Frame: Baseline; 1 month after the end of treatment; every 3 months for the first 2 years; every 6 months in years 4 and 5; and annually after year 5.

Cosmesis assessed by the physician using the Harvard Breast Cosmesis Scale. This is a 4-point categorical scale: Excellent (treated breast nearly identical to the untreated breast), Good (slight difference between breasts), Fair (obvious difference between breasts but without major distortion), and Poor (marked distortion of the treated breast). Higher scores (Poor) indicate worse cosmesis. The physician completes the assessment independently.
Baseline; 1 month after the end of treatment; every 3 months for the first 2 years; every 6 months in years 4 and 5; and annually after year 5.
Patient-reported Harvard Breast Cosmesis Scale
Time Frame: Baseline; 1 month after the end of treatment; every 3 months for the first 2 years; every 6 months in years 4 and 5; and annually after year 5.

Cosmesis assessed by the patient using the Harvard Breast Cosmesis Scale. This is a 4-point categorical scale: Excellent (treated breast nearly identical to the untreated breast), Good (slight difference between breasts), Fair (obvious difference between breasts but without major distortion), and Poor (marked distortion of the treated breast). Higher scores (Poor) indicate worse cosmesis. The patient completes the assessment independently.
Baseline; 1 month after the end of treatment; every 3 months for the first 2 years; every 6 months in years 4 and 5; and annually after year 5.
Quality of Life - EORTC QLQ-C30 (Serbian version)
Time Frame: Baseline; 1 month after the end of treatment; every 3 months for the first 2 years; every 6 months in years 4 and 5; and annually after year 5.

The Serbian translation of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30), validated for the Serbian-speaking population, will be used to assess quality of life. This questionnaire consists of 30 items grouped into functional scales, symptom scales, a global health status/QoL scale, and single-item symptom scales. Responses are converted to a 0 to 100 scale. For functional and global QoL scales, higher scores indicate better functioning/QoL. For symptom scales, higher scores indicate greater symptom severity.
Baseline; 1 month after the end of treatment; every 3 months for the first 2 years; every 6 months in years 4 and 5; and annually after year 5.
Quality of Life - EORTC QLQ-BR23 (Serbian version)
Time Frame: Baseline; 1 month after the end of treatment; every 3 months for the first 2 years; every 6 months in years 4 and 5; and annually after year 5.

The Serbian translation of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Breast Cancer Module (EORTC QLQ-BR23), validated for the Serbian-speaking population, will be used to assess breast cancer-specific quality of life. This 23-item module includes functional scales (body image, sexual functioning, sexual enjoyment, future perspective) and symptom scales (systemic therapy side effects, breast symptoms, arm symptoms, upset by hair loss). Scores are converted to a 0 to 100 scale. For functional scales, higher scores indicate better functioning. For symptom scales, higher scores indicate greater symptom severity.
Baseline; 1 month after the end of treatment; every 3 months for the first 2 years; every 6 months in years 4 and 5; and annually after year 5.

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Oncology Institute of Vojvodina

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2036

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 8, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 19, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 22, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • NS-dojka-SRB

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The analyzed data from the study will be published in scientific journals. We are prepared to share our data for analysis with researchers from similar studies (previously registered on ClinicalTrials.gov) to compare our results.

IPD Sharing Time Frame

The expected time for the publication of the first data is in 3 years (2026).

IPD Sharing Access Criteria

Contact the researchers via email.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

Yes

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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