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

Background Within the context of metastatic colorectal cancer, patients with Eastern Cooperative Oncology Group (ECOG) performance score 0-1 are usually pooled together in clinical practice guidelines and clinical trials' reports. The current study aims to delineate potential differences in outcomes between metastatic colorectal cancer patients with ECOG score 0 versus 1 who are treated with currently accepted first-line fluorouracil (5FU)-based chemotherapy. Methods The current study is based on a pooled dataset from five clinical trials of 5FU-based treatment for metastatic colorectal cancer (NCT00272051; NCT00115765; NCT00305188; NCT00364013; and NCT00384176). Patients with metastatic colorectal cancer and ECOG score of 0-1 were eligible for the current study. Multivariable logistic regression analysis was used to assess the relationship between ECOG performance status and the development of different toxicities. Kaplan-Meier survival estimates were used to clarify the impact of the ECOG score on overall and progression-free survivals. Multivariable Cox regression analysis was then used to evaluate the impact of ECOG score on overall and progression-free survivals. Results A total of 3143 patients were included in the current analysis. Within multivariable logistic regression analysis, patients with an ECOG score of 0 have a lower probability of serious adverse events (OR 0.678; 95% CI 0.583-0.788; P < 0.001), fatal adverse events (OR 0.552; 95% CI 0.397-0.766; P < 0.001), high-grade anemia (OR 0.426; 95% CI 0.252-0.721; P = 0.001), and high-grade nausea/vomiting (OR 0.697; 95% CI 0.509-0.955; P = 0.024). Through Kaplan-Meier survival analysis, patients with an ECOG score of 0 have better overall and progression-free survivals (P < 0.001 for both endpoints). Median overall survival was 27.63 months among patients with an ECOG score of 0 versus 20.00 months among patients with an ECOG score of 1. Within multivariable Cox regression analysis, patients with ECOG score of 0 were associated with better overall and progression-free survivals (HR for overall survival 0.613; 95% CI 0.556-0.676; P < 0.001); (HR for progression-free survival 0.765; 95% CI 0.705-0.829; P < 0.001). Conclusion 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.