Sigmoid Colon Organ Motion in Radiotherapy

Study Overview
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Brief Summary
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Radiotherapy is used in cancer treatment to eradicate microscopic cancer cells to lower the risk of recurrence. The radiotherapy plan must account for organ movement inside the body to ascertain adequate dose is delivered to the target. Knowledge of the magnitude is crucial to radiotherapy treatment planning. This study aims to quantify the movement of the sigmoid colon between different fractions of radiotherapy treatment (interfraction motion) and within the same fraction (intrafraction motion). This knowledge will help us determine the optimal margin to use in radiotherapy treatment planning.

Detailed Description
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Day-to-day positioning variations contribute to uncertainty in radiotherapy. The International Commission on Radiation Units and Measurements (ICRU) report 62 recommended a margin added to the clinical target volume (CTV) to produce the planning target volume (PTV). In ICRU report 83, this concept is further extended and refined to yield the internal target volume (ITV), which is defined as CTV plus a margin to account for uncertainty within the patient. Image-guided radiotherapy (IGRT) has been developed as a method to lower the margin required in PTV expansion. In current practice, IGRT methods mostly rely on bony anatomy alignment. Due to its nature, internal organ motion cannot be compensated by IGRT. Therefore, an ITV expansion is still required. The optimal ITV expansion margin depends on the magnitude of internal organ motion; the smallest margin that provides adequate coverage is preferred. In this study, we aim to quantify organ motion of the sigmoid colon anastomosis site during radiotherapy treatment, including movement between fractions (interfraction) and movement within the same fraction (intrafraction).

Official Title
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Interfraction and Intrafraction Organ Motion of the Sigmoid Colon in Patients With Colorectal Cancer Undergoing Adjuvant Radiotherapy

Conditions
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Sigmoid Cancer, Sigmoid Colon Cancer

Intervention / Treatment
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* Radiation: Adjuvant image-guided radiotherapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with pathologically confirmed sigmoid colon cancer, who have received surgical excision (AR or LAR). Anastomosis of the colon must be performed with a surgical stapler, with the staple visible on CT imaging. Exclusion Criteria: Gross recurrent disease (defined as visible mass on CT imaging) in the pelvis. Other malignancy within the pelvic cavity. Previous surgery to the pelvic cavity other than AR/LAR. Pregnant or lactating females. Subjects who, in the opinion of the Investigator, may be non-compliant with study schedules or procedures.

Ages Eligible for Study
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Minimum Age: 20 Years

Sexes Eligible for Study
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All

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
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Adjuvant image-guided radiotherapy<br>Adjuvant radiotherapy with image guidance via cone beam computed tomography. Treatment is identical to the current standard of care. | Radiation: Adjuvant image-guided radiotherapy<br>* Image-guided adjuvant radiotherapy to the sigmoid colon surgical tumor bed and pelvic regional lymph nodes: 45-50.4 Gy in 1.8 Gy/fraction<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Interfraction sigmoid colon organ motion | Offset of the sigmoid colon staple site in three axes (anterior-posterior, lateral, and cranial-caudal) compared to simulation CT | 90 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intrafraction sigmoid colon organ motion | Offset of the sigmoid colon staple site in three axes (anterior-posterior, lateral, and cranial-caudal) between pre-treatment cone beam computed tomography (CBCT) and post-treatment CBCT | 90 days | 
| Setup errors | Offset of couch (set-up error) when matching the pre-treatment CBCT with simulation CT | 90 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Sigmoid colon cancer, Internal organ motion, Radiotherapy