Use of Positron Emission Tomography/Computed Tomography (PET/CT) to Assess Tumor Response to Neoadjuvant Treatment for Distal Rectal Cancer

Study Overview
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Brief Summary
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Preoperative chemoradiation therapy is the preferred initial treatment option for distal rectal cancers. However, assessing tumor response to preoperative chemoradiation therapy remains a challenge to the colorectal surgeon, especially when determining if there is a complete response, observed in more than 10% of cases. The purpose of this study is to evaluate the use of the PET/CT in assessing distal rectal tumor response to preoperative chemoradiation therapy.

Detailed Description
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Patients with distal rectal adenocarcinoma will be submitted to an initial whole body PET/CT prior to the preoperative chemoradiation therapy with 5-fluorouracil and 5040 cGy. Six weeks and 12 weeks after the preoperative treatment is finished the PET/CT will be repeated. At 1 and at 2 years after preoperative treatment is concluded another PET/CT will be performed. The colorectal surgeon evaluating the response to chemoradiation therapy will be blinded to the results of the PET/CT, as the radiologist will be blinded to the response assessment. PET/CT results will not be used to determine treatment strategy, unless metastatic disease or other disease is diagnosed. Patients with a complete clinical response at 8 weeks will be rigorously followed while patients with an incomplete clinical response at 8 weeks will be submitted to radical surgery. PET/CT results will be compared to current radiological studies and final pathological reports.

Official Title
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Study of the Value of the PET/CT in Evaluating the Response of Distal Rectal Cancer to Neoadjuvant Chemoradiation Therapy

Conditions
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Rectal Cancer

Intervention / Treatment
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* Device: PET/CT with FDG


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of Rectal Adenocarcinoma Location of Tumor less than 7cm from Anal Verge Exclusion Criteria: Pregnancy or Nursing Metastatic Disease (Stage IV disease) Previous treatment for any cancer Patients clinically unable to receive neoadjuvant chemoradiotherapy Hypersensitivity to 18FDG

Ages Eligible for Study
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Minimum Age: 18 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: Diagnostic
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: PET/CT<br>Single arm study evaluating the use of PET/CT to assess rectal cancer response to neoadjuvant therapy | Device: PET/CT with FDG<br>* PET/CT before start of neoadjuvant CRT, at 6 weeks, 12 weeks, following CRT completion and 12mo, 24mo following CRT for those considered complete responders<br>* Other names: PET-CT;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PET/CT specificity and sensitivity for tumor response |  | Response assesment at 6 and 8 weeks following neoadjuvant therapy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between PET/CT and complete clinical Response |  | 2 years following completion of neoadjuvant therapy | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Rectal Cancer, Positron Emission Tomography, Fluorodeoxyglucose F18, Computed Tomography, Neoadjuvant Therapy, Chemotherapy, Radiotherapy