Progression-free Survival as a Surrogate End-point in Advanced Colorectal Cancer Treated with Antiangiogenic Therapies.

Background: It is not clear if progression-free survival (PFS) is a good surrogate end-point for overall survival (OS) for metastatic colorectal cancer if antiangiogenic therapies are used.
Materials and Methods: We investigated randomized controlled trials testing antiangiogenic agents against chemotherapy. Log hazard ratios (HR) for PFS and OS were used to construct linear regression models. The surrogate threshold effect (STE) was calculated.
Results: Thirteen studies and 24 comparison arms were available, including 7,179 patients. This model returned a significant correlation between PFS and OS (R(2)=0.68, p<0.001) with an STE of 0.83. Analysis restricted to first-line gave similar results (R(2)=0.68, p<0.001, STE=0.75).
Conclusion: There is a significant correlation between the effect of treatment on PFS and OS. PFS remains a good surrogate end-point for OS even if anti-angiogenic agents are used.
(Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)