Surrogacy of progression free survival for overall survival in metastatic breast cancer studies: Meta-analyses of published studies

Conclusion: %ΔMEDPFS was found to be a better diagnostic measure for predicting significant HROS. Our analysis results also suggest that consideration of total number of deaths may further improve its diagnostic performance. Based on our study results, the studies with 50% improvement in median PFS are more likely to produce significant HROS if the total number of OS events at the time of analysis is 227 or more.