DRMST
This is defined as the expected difference in survival time between the research and control groups, ignoring survival after a certain time τ. Algebraically, this is the difference between the integrals of the survival functions for the two groups within a fixed time horizon τ
It corresponds to the difference between the areas under the two survival curves. One advantage of DRMST is that its interpretation does not rely on the proportional hazards assumption. Another one is that it accounts for survival at each time point within the selected interval [0, τ], rather than just focusing on survival at time DRMST is a measure of absolute difference between the arms; it can be estimated in various ways, and this might be using a proportional hazards model, but does not lose its interpretation in the absence of proportional hazards.