ECOG performance score 0 versus 1: impact on efficacy and safety of first-line 5-FU-based chemotherapy among patients with metastatic colorectal cancer included in five randomized trials.

Compared with patients with ECOG score of 1, patients with ECOG score of 0 have better overall and progression-free survival, and less probability of serious and fatal adverse events. This distinction in outcomes should be noted when choosing appropriate therapeutic strategies and when designing/reporting the results of clinical trials.