External Beam Radiation Therapy - Target Volume

Study Overview
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Brief Summary
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Delivery of conformal radiation therapy following radical prostatectomy is limited by the inability to define the clinical target volume (CTV). This stems from a poor understanding of patterns of local recurrence and limitations of standard imaging techniques.Magnetic Resonance Imaging (MRI) is a promising modality for imaging the prostatic bed following radical prostatectomy. MRI provides more detailed postoperative anatomy to guide CTV delineation, the ability to document local recurrence patterns, and a method to assess intrafraction prostatic bed motion and deformity to define appropriate planning target volume margins. The aim of this pilot study is to develop a technique for external beam radiation therapy (EBRT) following radical prostatectomy based on MRI-delineation of the CTV. Twenty patients will be enrolled in this pilot, development phase.

Official Title
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A Pilot Study to Develop a Technique for External Beam Radiotherapy After Radical Prostatectomy Based on MRI-Delineation of the Clinical Target Volume

Conditions
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Prostatic Neoplasms

Intervention / Treatment
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* Procedure: External Beam Radiotherapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients following radical prostatectomy for prostate adenocarcinoma with one or more of the following adverse features: pT2 + positive surgical margins ) pT3 ) PSA ≤ 2ng/ml Persistently elevated PSA at 3 months ) Patients with initially undetectable PSA following prostatectomy for prostate adenocarcinoma with subsequent PSA relapse Patients being planned for radiation therapy No evidence of distant metastases Age ≥ 18 years ECOG performance status 0 or 1 Informed consent Exclusion Criteria: Contraindications to MRI Patients weighing >136 kgs (weight limit for the scanner tables) Patients with pacemakers, cerebral aneurysm clips, shrapnel injury or implantable electronic devices not compatible with MRI. Severe claustrophobia Inflammatory bowel disease or collagen vascular disease Previous colorectal surgery Previous pelvic radiotherapy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

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: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: External Beam Radiation Therapy<br> | Procedure: External Beam Radiotherapy<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To develop a technique for MRI-delineation of the clinical target volume (CTV) for EBRT following radical prostatectomy |  | After data acquisition | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To compare the reproducibility of clinical target volume and rectal wall volume delineation on MRI and CT. |  | After data acquisition | 
| To compare the location of the urethral anastomosis defined on MRI as compared to a fiducial marker placed under TRUS-guidance adjacent to the anastomosis. |  | After data acquisition | 
| To measure the amount of intrafraction movement and deformity of the prostatic bed and seminal vesicles with current bowel regimen of daily milk of magnesia using cinematic MRI. |  | After data acquisition | 
| To determine the optimal radiation technique that encompasses the MRI-defined PTV whilst respecting bowel and bladder dose constraints. |  | After data acquisition | 
| To measure the amount of interfraction movement and deformity of the bladder, rectum, and surgical clips within the operative bed using daily cone-beam CT imaging. |  | After data acquisition | 
| To explore the utility of IV contrast for the delineation of gross tumor recurrence and normal blood vessels. |  | After data acquisition |