PET Evaluation of Response After 1 Course of Chemotherapy as Predictor of Treatment Outcome.

Study Overview
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Brief Summary
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Study hypothesis : early decrease in fdg-pet measured SUV max after 1 cycle of chemotherapy can accurately predict response of chemotherapy as assessed by conventional radiology after 3 cycles of chemotherapy. FDG-PET imaging will be done at J0 and J14 of a new line of chemotherapy treatment in metastatic colorectal cancer. SUV max will be recorded and delta SUVmax will be compared to the results of conventional radiological evaluation after 3 courses of chemotherapy. Results will also be compared to the time to disease progression.

Detailed Description
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statistical hypothesis : Sample size calculation for FDG-PET in metastatic patients. In the paper of Cascini et al. [1], they have 18 patients with a TRG response (TRG = Tumor Regression Grade) and 15 patients with no response. SUV mean was measured at baseline and at day 12 in all 33 patients. All 33 patients showed a reduction in SUV-mean from baseline to day 12. The median reduction in SUV-mean was 63% (mean 66%) in responding tumors and 22% (mean 22%) for non responding tumors. Using a cutoff level of 52% a perfect accuracy could be obtained, i.e. all responding tumors had a SUV-mean reduction higher than 52% and all non responding tumors had a SUV-mean reduction lower than 52%. (Standard deviation of the SUV-mean reduction was 25.) All 33 patients showed also a reduction in SUV-max from baseline to day 12. The median reduction in SUV-max was 62% in responding tumors and 28% in non responding tumors. (No information about mean or standard deviation of SUV-max available in [1].) Based on the data of SUV-mean we can do a power calculation based on the Wilcoxon test: In order to demonstrate an absolute difference in the mean of ΔSUV-mean of 44% between responding and non responding patients, with an estimated standard deviation of 25, using 35 patients (50% response, 50% no response), at a significance level of 5%, we obtain a power of 0.98. For SUV-max, if we assume that the difference in the means is similar to the difference in the medians, i.e. 34% and the standard deviation is similar to the one of SUV-mean, i.e. 25, we obtain a power of 0.93 If we, to be safe, are a little bit less optimistic and estimate that the difference in the mean of ΔSUV-max between responding and non responding tumors would be a little lower than in [1]: 35%, and the standard deviation a little bit higher: 30, then we need 40 patients at a power of 0.90 Référence 1 : Cascini GL, Avallone A, Delrio P, Guida C, Tatangelo F, Marone P et al.: F-18-FDG PET is an early predictor of pathologic tumor response to preoperative radiochemotherapy in locally advanced rectal cancer. Journal of Nuclear Medicine 2006, 47: 1241-1248.

Official Title
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Evaluation of Prognostic and Predictive Value of PETSCAn in ColoRectal Cancer (CRC)

Conditions
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Colorectal Cancer Metastatic, Early Response Evaluation, Fdg-PET

Intervention / Treatment
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* Procedure: FDG-PET imaging


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: advanced colorectal cancer evaluable disease signed informed consent Exclusion Criteria: no other cancer no other life-threatening condition unwillingness or inability to sign informed consent active cerebral metastasis

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| 1<br>all study population | Procedure: FDG-PET imaging<br>* FDG-PET imaging at D0 and D14 of first course of a new chemotherapy for advanced colorectal cancer<br>* Other names: PET-CT SCan;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| compare fdg-pet variations after 1 course of chemotherapy to chemotherapy outcome measured by time to disease progression |  | Time to Disease progression | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| compare fdg-pet variations after 1 course of chemotherapy to chemotherapy outcome measured by tumour response rate following RECIST criteria. |  | response rate | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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metastatic colorectal cancer, fdg pet, response evaluation