Sidenote: Visually comparing estimated survival curves in order to assess whether there is a difference in survival between groups is usually not recommended, because it is highly subjective. Statistical tests such as the log-rank test are usually more appropriate.

Note that, the confidence limits are wide at the tail of the curves, making meaningful interpretations difficult. This can be explained by the fact that, in practice, there are usually patients who are lost to follow-up or alive at the end of follow-up. Thus, it may be sensible to shorten plots before the end of follow-up on the x-axis (Pocock et al, 2002).