In this multicentre , open-label , randomised , phase @ study we randomly assigned patients with rectal adenocarcinoma , clinically staged as cT@-@ or any node-positive disease , to two groups : a control group receiving standard fluorouracil-based combined modality treatment , consisting of preoperative radiotherapy of @ Gy in @ fractions plus infusional fluorouracil ( @ mg/m ( @ ) on days @-@ and @-@ ) , followed by surgery and four cycles of bolus fluorouracil ( @ mg/m ( @ ) on days @-@ and @ ) ; or to an investigational group receiving preoperative radiotherapy of @ Gy in @ fractions plus infusional fluorouracil ( @ mg/m ( @ ) on days @-@ and @-@ ) and oxaliplatin ( @ mg/m ( @ ) on days @ , @ , @ , and @ ) , followed by surgery and eight cycles of oxaliplatin ( @ mg/m ( @ ) on days @ and @ ) , leucovorin ( @ mg/m ( @ ) on days @ and @ ) , and infusional fluorouracil ( @ mg/m ( @ ) on days @-@ and @-@ ) .