Postoperative Radiation of Patients With Breast Cancer in Extreme Hypofractionation.

Study Overview
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Brief Summary
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Evaluation of treatment toxicity of extreme hypofractionation of the whole breast in five fractions of 5.2 Gy in five consecutive workdays.

Detailed Description
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The focus of this phase 2-trial is set on feasibility as well as early and late toxicity rates. One possible disadvantage of extreme hypofractionation could be an increased rate of fibrosis within the irradiated region. Therefore, a closer look will be taken with this prospective trial. In addition, we are planning an accompanying translational research program since hypofractionated schedules are suggested to be more immunogenic in breast cancer. Secondary objectives therefore are: cosmetic outcome, local tumor control, quality of life, dynamic immune status, importance of tumor infiltrating immune cells, overall survival, disease-free survival, feasibility of breath-hold radiation technique.

Official Title
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Postoperative External Beam Whole Breast or Chest Wall Irradiation of Patients With Breast Cancer in Extreme Hypofractionation.

Conditions
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Breast Cancer

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Histologically confirmed invasive breast cancer or ductal carcinoma in situ (DCIS) pT-category pT0-3 complete resection (R0) Absence of distant metastasis (M0) Absence of contralateral breast cancer/ DCIS Karnofsky Performance Score ≥ 60% Age ≥ 18 years at time of study entry Written informed consent Exclusion Criteria: All patients not fulfilling inclusion criteria Morbus Paget or pathological skin infiltration Earlier or synchronous breast cancer Pregnant or breast-feeding women Increased radiosensitivity or any genetic disposition for increased radiosensitivity, e.g. ataxia telangiectatica Judgement by the investigator that the patient is unlikely to comply with study procedures and requirements

Ages Eligible for Study
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Minimum Age: 18 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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence and grade of Treatment related adverse events according to the Common Terminology Criteria for Adverse Events (CTCAE 5.0) | Evaluation during treatment and at each follow-up visit up to 10 years | 08/2022 - 07/2035 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cosmetic results according to the Harvard-scale | Clinical evaluation of the irradiated breast at each follow-up up to 10 years according to the Harvard-scale (patient's and physician's view) | 05/2022 - 04/2035 | 
| In-breast recurrence rate | Evaluation at each follow-up up to 10 years via regular examinations including mammography/ ultrasound | 05/2022 - 04/2035 | 
| Quality of life during and after treatment using the patient-reported questionnaires EORTC QLQ-C30 and QLQ-BR23 | Evaluation of patient's quality of life from inclusion to each follow-up up to 10 years via standardized questionnaires: European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire QLQ-C30 and the breast-orientated QLQ-BR23 | 05/2022 - 04/2035 | 
| Immune status analysis: Immunophenotyping using peripheral blood at several time points | Withdrawals of whole blood (plasma and serum) before the first irradiation until one year after the treatment. Immunophenotyping by a modular multicolor flow cytometry-based method. Furthermore, whole exome sequencing/RNASeq on already obtained tissue from the breast surgery. | 05/2022 - 04/2027 | 
| Overall survival | Evaluation at each follow-up up to 10 years | 05/2022 - 04/2035 | 
| Evaluation of feasibility of breath-hold radiation technique throughout the treatment time | Evaluation of patient's capability to follow breathing commandos during planning-CT scan and each application of radiotherapy | 05/2022 - 04/2025 |