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

Study Overview
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Brief Summary
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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.

Detailed Description
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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 (for left breast radiation therapy, active breath control is used - in deep inspiration or respiratory gating).

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

Conditions
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Breast Cancer Female

Intervention / Treatment
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* Radiation: Ultra-fractionated WBI
* Radiation: Ultra-fractionated PBI


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Partial Breast Irradiation<br> | Radiation: Ultra-fractionated PBI<br>* An ultra-short course of radiotherapy with 26Gy in 5 fractions will be administered to the part of the breast where the tumor was located.<br>|
| Experimental: Whole Breast Irradiation<br> | Radiation: Ultra-fractionated WBI<br>* An ultra-short course of radiotherapy with 26Gy in 5 fractions will be administered to the whole breast where the tumor was located.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acute toxicity | Assessment of acute toxicity of radiotherapy in two radiotherapy regimens. Acute toxicity will be scored according to the Common Terminology Criteria for Adverse Events (CTCAE) scale version 5.0 | 1-6 months after RT | 
| Late toxicity | Assessment of late toxicity of radiotherapy in two radiotherapy regimens. Acute toxicity will be scored according to the Common Terminology Criteria for Adverse Events (CTCAE) scale version 5.0 | 6-60 months after RT | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Local-regional control | Any newly suspicious skin change/s or palpable lymph node in the irradiated area that is/are pathologically proved to be locoregional tumor recurrence. | 3, 5 and 10 years | 
| Disease-free survival | Disease-free survival refers to the time from adjuvant radiotherapy of breast cancer to clinically confirmed local recurrence, distant metastasis, second primary tumor diagnosis, or patient death. | 3, 5 and 10 years | 
| Overall Survival | Time from adjuvant radiotherapy to death. | 3, 5 and 10 years | 
| Distant metastasis occurrence | The time from adjuvant radiotherapy to the occurrence of distant metastasis. | 3, 5 and 10 years | 
| Cosmetic outcome | The Harvard score for breast cosmesis (a 4-grade scale) will be used, which will be independently filled out by both patients and physicians. | at baseline, during the radiotherapy, immediately after radiotherapy termination and then in the first 2 years every 3 months, in the 4th and 5th year every 6 months and after 5 years once per year. | 
| QoL assessment | We will use the EORTC QLQ-BR23 questionnaire validated for the Serbian-speaking population to assess the quality of life. | at baseline, during the radiotherapy, immediately after radiotherapy termination and then in the first 2 years every 3 months, in the 4th and 5th year every 6 months and after 5 years once per year. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ultra-hypofractionated radiotherapy, Partial breast irradiation, Breast radiotherapy toxicity