BACKGROUND: Despite lack of a true comparative study, the folfox 
(5-fluorouracil-leucovorin-oxaliplatin) and capox (capecitabine-oxaliplatin) 
regimens are believed to be similar in their efficacy and tolerability in the 
treatment of stage iii colorectal cancer. However, that belief has been 
disputed, because real-life data suggest that the capox regimen is more toxic, 
leading to more frequent reductions in the delivered dose intensity-thus raising 
questions about the effect of dose intensity on clinical outcomes.
METHODS: A retrospective data review for two Canadian institutions, the Segal 
Cancer Centre and the Tom Baker Cancer Centre, considered patients diagnosed 
with stage iii colorectal cancer during 2006-2013. Primary endpoints were dose 
intensity and toxicity, with a secondary endpoint of disease-free survival.
RESULTS: The study enrolled 180 eligible patients (80 at the Segal Cancer 
Centre, 100 at the Tom Baker Cancer Centre). Of those 180 patients, 75 received 
capox, and 105 received mfolfox6. In the capox group, a significant dose 
reduction was identified for capecitabine compared with 5-fluorouracil in 
mfolfox6 group (p = 0.0014). Similarly, a significant dose reduction was 
observed for oxaliplatin in mfolfox6 compared with oxaliplatin in capox (p = 
0.0001). Compared with the patients receiving capox, those receiving mfolfox6 
were twice as likely to experience a treatment delay of more than 1 cycle-length 
(p = 0.03855). Toxicity was more frequent in patients receiving mfolfox6 
(nausea: 30% vs. 18%; diarrhea: 47% vs. 24%; peripheral sensory neuropathy: 32% 
vs. 3%). At a median follow-up of 40 months, preliminary data showed no 
difference in disease-free survival (p = 0.598). Pooled data from both 
institutions were also separately analyzed, and no significant differences were 
found.
CONCLUSIONS: Our results support the use of capox despite a lack of head-to-head 
randomized trial data.