With an overall median follow-up of @ months ( @ % CI @-@ @ ) and @ ( @ % ) of @ required events observed , progression-free survival was significantly shorter in the chemotherapy plus cetuximab group than in the chemotherapy alone group ( @ months -LSB- @ % CI @-@ @ -RSB- vs @ months -LSB- @ % CI @-@ @ -RSB- , hazard ratio @ , @ % CI @-@ @ , p = @ ) .