The Influence of Treatment Position (Prone vs. Supine) on Whole Breast Target

Study Overview
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Brief Summary
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Radiotherapy after breast conserving therapy plays an important role in early stage breast cancer patients. It not only results in a reduction in local and regional recurrence but also decrease the death rate effectively. For adjuvant radiotherapy, supine positioning is the most common approach and has multiple advantages. Due to deformability and softness of the breast, during simulation and treatment in supine position, the breast stretches over the chest wall, especially in patients with large and pendulous glands. Thus the organs at risk (OARs) received dose increased. The radiotherapeutic toxicity are unavoidable. Some present studies show that the prone positioning of patients can improve dose homogeneity and reduce the dose distribution in OARs in patients with large and pendulous glands. Chinese women have relatively small breasts, the advantages of those have not been established. Therefore, investigators compared the parameters between supine and prone positions for whole breast irradiation after conserving surgery.

Detailed Description
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Objective To investigate the difference of target volumes and dosimetric parameters between supine and prone positions for whole breast irradiation after conserving surgery. Methods Breast cancer patients with T1-2N0M0 stage who underwent radiation therapy after conserving surgery were enrolled. Supine and Prone scan sets were acquired during free breathing for all patients. Target volumes and organs at risk (OARs) including heart, ipsilateral lung and bilateral breast were contoured by the same radiation oncologist. The tumor bed (TB) was determined based on surgical clips. The Clinical target volume (CTV)consisted of the whole breast. The planning target volume (PTV) was CTV plus 0.5cm. The boost of PTV (PTVboost) was TB plus 0.5cm. Dosimetric parameters of target volumes and OARs were compared between supine and prone position.

Official Title
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The Influence of Treatment Position (Prone vs. Supine) on Whole Breast Irradiation for Chinese Breast Cancer Patients :Comparative Study

Conditions
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Breast Cancer

Intervention / Treatment
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* Device: dedicated treatment board with no degree


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Breast cancer patients with T1-T2N0M0 stage who underwent radiation therapy after conserving surgery exhibited normal arm movement aſter surgery had no chronic lung diseases Written informed consent forms Exclusion Criteria: Breast cancer patients with radical surgery could not exhibit normal arm movement after surgery had chronic lung diseases refused informed consent forms

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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
Intervention Model: Single Group Assignment
Interventional Model Description: Breast cancer patients with T1-T2N0M0 stage who underwent radiation therapy after conserving surgery were enrolled. Supine and Prone scan sets were acquired during free breathing for all patients. Target volumes and organs at risk (OARs) including heart, ipsilateral lung and bilateral breast were contoured by the same radiation oncologist.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Breast cancer underwent scanning in the supine position<br>Breast cancer patients with T1-2N0M0 stage who underwent radiation therapy after conserving surgery were enrolled. Supine scan sets were acquired during free breathing for all patients. Target volumes and organs at risk (OARs) including heart, ipsilateral lung and bilateral breast were contoured by the same radiation oncologist. The tumor bed (TB) was determined based on surgical clips. The Clinical target volume (CTV)consisted of the whole breast. The planning target volume (PTV) was CTV plus 0.5cm. The boost of PTV (PTVboost) was TB plus 0.5cm. | Device: dedicated treatment board with no degree<br>* the patients were placed in the prone position on a dedicated treatment board with no degree incline using an arm support (with both arms above the head). Te board contained an open aperture on one side to allow for the ipsilateral breast to hang freely away from the chest wall<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| dose distribution of GTV | the difference of GTV (Gross tumor target) between two plans | 1 year | 
| dose distribution of CTV | the difference of CTV (clinical target volume) between two plans | 1 year | 
| dose distribution of PTV | the difference of PTV (planing target volume) between two plans | 1 year | 
| dose distribution of heart | the difference of heart dose distribution between two plans | 1 year | 
| dose distribution of ipsilateral lung | the difference of ipsilateral lung dose distribution between two plans | 1 year | 
| dose distribution of bilateral breasts | the difference of bilateral breasts dose distribution between two plans | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Breast cancer, radiotherapy