BACKGROUND: No differences in response rate (RR), progression-free survival (PFS), overall survival (OS) and quality of life (QoL) were seen in patients randomly treated with biweekly oxaliplatin plus either fluorouracil/folinic acid or capecitabine. METHODS: We investigated the independent effect of baseline clinical characteristics and physical functioning (PF) domain on RR, PFS, and OS in 310 patients who completed the EORTC QLQ-C30 questionnaire. Multivariate analyses stratified by treatment were performed. An exploratory analysis was done by grouping patients with a PF score superior or equal to the highest quartile (n = 111), included between the highest and the lowest quartiles (n = 99), or inferior to the lowest quartile (n = 100). The relationship between these three groups and the ECOG PS was then analysed. RESULTS: At multivariate analysis, OS was negatively affected by the number of metastatic sites, the serum alkaline phosphatase, and the ECOG PS, while it was positively affected by the previous surgical resection of the primary tumour. Adding the baseline PF score, the number of disease sites (p