Examining survival data.

This brief review presents a nonmathematical description of the methods used to describe the outcome of patient groups when the time to an event such as death or disease recurrence is of interest. Calculation of the product-limit, actuarial and relative survival curves is described and the underlying principles are explained. Two statistical tests frequently used in comparing survival curves (the generalized Wilcoxon and the log-rank or Mantel test) are described and an example of their use is given.