The planed treatment duration per patient is 16 weeks. Patients achieving a response or stable disease after 16 weeks of treatment may continue study medication for 6 more months (patients receiving Cetuximab alone) or for 3 more months (patients receiving Cetuximab plus Dexamethasone). Responding patients who relapse during follow-up period of two years may receive a second treatment with Cetuximab following initial study guidelines