Elaboration of a Model for Predicting Efficacy of Monoclonal Antibodies (Cetuximab and Bevacizumab) in Patients With Colorectal Cancer and Liver Metastases

Primary Objective: This trial is elaborating a model for rapidly predicting (day 21) the response to monoclonal antibodies anti-EGFR and anti-VEGF (cetuximab and bevacizumab) based on biological markers and/or functional imaging. The response to treatment is evaluated by the conventional method after 2 months (Response Evaluation Criteria in Solid Tumors [RECIST] criteria).
Secondary Objectives:
1. This trial is also analyzing the correlation between the magnitude of response to treatment at 2 months (stabilization or objective response, RECIST criteria) and that of response observed after 6 months of treatment.
2. The organisational objective is to develop a tumour bank of metastatic colorectal cancer.
Population: The population includes 252 male and female patients with metastatic colorectal cancer justifying the use of cetuximab or bevacizumab, with no heart disease.
Techniques: Computed tomography (CT scan), functional imaging (ultrasound with SonoVue); molecular imaging (positron emission tomography [PET] with fluorodeoxyglucose F18 [18-FDG]); and biology and pathology on microbiopsy of liver metastasis are used.
Outcome Criteria: The primary outcome is response to treatment with monoclonal antibodies according to RECIST criteria at two months.
Studied Factors:
Radiology:
1. CT scan: RECIST criteria (gold standard);
2. Ultrasound with SonoVue injection: 1 representative target (delay of contrast appearance, peak of rising, curve of increase and decrease of the signal, area under the curve, time of average transit).
Nuclear Medicine: PET scan and 18-FDG (standard uptake values [SUV])
Molecular Characterization of Tumors: p53 status; microsatellite instability (MSI) status; expression of oncogenes; EGFR status; VEGF status; determination of FcgammaRIIIA polymorphisms
Statistics:
1. Descriptive analyses;
2. Analysis of the appropriate threshold to measure: response to treatment by an ultrasound with SonoVue and by PET scan; correlation between response predicted by the ultrasound with SonoVue and the PET; conventional morphological CT at 2 months
3. Analysis of prognostic factors:
1. Evaluation of the role of each prognostic factor (pathology and imaging) on response to treatment;
2. Multivariate analysis of prognostic factors;
3. Analysis of the prognostic power of early response at 2 months on the response observed after 6 months of treatment.