Patients aged @ years and older with stage III , IVa , or IVb , previously untreated , measurable ( @ mm for at least one dimension ) , locally advanced squamous-cell carcinoma of the head and neck ( non-nasopharygeal ) and an Eastern Cooperative Oncology Group performance status of @-@ were randomly assigned ( @:@ ) by an independent vendor to open-label chemoradiotherapy ( two cycles of cisplatin @ mg/m ( @ ) during radiotherapy ) or to radiotherapy plus panitumumab ( three cycles of panitumumab @ mg/kg every @ weeks administered with radiotherapy ) using a stratified randomisation with a block size of five .