Progression-free survival as a surrogate endpoint of overall survival in patients with metastatic colorectal cancer

Background: In many clinical trials designed to assess the efficacy of anticancer treatments, overall survival (OS) is often used as a primary endpoint despite its several points of weakness. Methods: This study evaluated the role of progression-free survival (PFS) in the first three lines of treatment as a potential surrogate endpoint of OS in patients with metastatic colorectal cancer (MCRC). One hundred and twenty patients with MCRC were enrolled in this study. The median PFS of the first-, second-, and third-lines of treatment and the OS were evaluated. The correlation between the time to progression and the OS was analyzed. The median PFS of the three lines of treatment were 8.5, 5, and 3 months, respectively. Results: The median OS was 32.4 months. A modest correlation was found between the PFS to the first-line treatment with Folfox–avastin and OS. Similar data were obtained with the second-line treatment. However, no correlation was found between the PFS and OS during the third-line treatment. The regression analysis revealed that PFS is predictive of OS. Conclusion: In brief, the PFS of the first- and second-lines of treatment could be a good candidate as a surrogate endpoint of OS in patients with MCRC.