Fig. 4.

Relationship between median overall survival (OS) and median time to progression (TTP) or progression-free survival (PFS) (a), and between median OS and median postprogression survival (PPS) (b), among all trials. Each trial is represented by a circle, with its size proportional to the number of patients. The correlation between median OS and median TTP or PFS was not strong (R = 0.50, p < 0.001), whereas the correlation between median OS and median PPS was strong (R = 0.78, p < 0.001) based on weighted linear regression (*).