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.