Progression-Free Survival and Time to Progression as Real Surrogate End Points for Overall Survival in Advanced Breast Cancer: A Meta-Analysis of 37 Trials

Both PFS and TTP can be considered valid surrogate end points for OS in the trials of targeted therapy-based treatments and clinical benefits for ABC. Further research is necessary to clarify the surrogacy of PFS/TTP for OS in other trials of targeted therapy-based treatments for ABC.