I am trying to make sense of what disease-free survival is (still new to medical research).
I was reading this article on the survival of patients after liver transplantation. In it, the author includes KM curves where one is overall survival (OS) and the other, disease-free survival (DFS). My initial understanding of DFS is survival time of patient for non-recurrence cohort. However, if that's the case then, the survival curve should be higher in DFS as compared to OS. The plots show OS being having better survival probability than DFS.
Does DFS mean:
- Still looking at death as event of interest, in addition patients that had recurred would have time-to-event as time to recurrence instead of time to death? or..
- Still looking at death as event of interest, in addition patients that had recurred would be censored?