The most frequent grade @-@ adverse events were mucosal inflammation ( @ -LSB- @ % -RSB- of @ patients in the chemoradiotherapy group vs @ -LSB- @ % -RSB- of @ patients in the radiotherapy plus panitumumab group ) , dysphagia ( @ -LSB- @ % -RSB- vs @ -LSB- @ % -RSB- ) , and radiation skin injury ( seven -LSB- @ % -RSB- vs @ -LSB- @ % -RSB- ) .