Optimalisatie van de behandeling met cetuximab voor patienten met uitgezaaide dikkedarm kanker door de opname van 89-zirconium gelabeld cetuximab te beoordelen middels PET-scan

Interventions: 89Zr-cetuximab PET scan: After a therapeutic dose of cetuximab, 10mg of 89Zr-cetuximab is injected. Six days after injection a PET-scan will be made. If this scan is considerd positive, meaning uptake in extra-hepatic metastases is present, the normal dose of cetuximab will be continued.
If the first PET-scan is negative, we will increase the dose of cetuximab (3 by 3 cohort design) and repeat the PET-scan. The patient will continue the higher dose biweekly.
Furthermore we will preform a 18F-FDG PET scan and 15O-H2O PET scan, on baseline and after 2 weeks of treatment, to evaluate early changes in respectively metabolic changes and changes in tumor perfusion.
At baseline and after 3-4 week of treatment a skin biopsy and tumor biopsy will be done. We will preform oncogenic mutation analysis, we will determine EGFR expression and saturation.
Primary outcome(s): 89Zr-cetuximab uptake in non-hepatic metastases (corrected VOIs) and the correlation with clinical benefit rate.
89Zr-cetuximab uptake in non-hepatic metastases with increased dosing of cetuximab (corrected VOIs).
The clinical benefit rate (CR, PR and SD) based upon 89Zr-cetuximab image adjusted dosing
Study Design: Non-randomized controlled trial, Open (masking not used), N/A , unknown, Parallel