### Survival Estimate Plot with PROC LIFETEST

This example is taken from Example 70.2 in ChapterĀ 70: The LIFETEST Procedure. It shows how to construct a product-limit survival estimate plot. Both the ODS GRAPHICS statement and procedure options are
used to request the plot. This examples uses the bone marrow transplant data set, which is available from the `Sashelp`

library. The data set contains disease-free times for three risk categories.

The following statements use PROC LIFETEST to compute the product-limit estimate of the survivor function for each risk category:

proc lifetest data=sashelp.BMT plots=survival(cb=hw test);
time T * Status(0);
strata Group / test=logrank;
run;

ODS Graphics was enabled in a previous step, and the PLOTS=SURVIVAL option requests a plot of the estimated survival curves.
The CB=HW suboption requests Hall-Wellner confidence bands, and the TEST suboption displays the p-value for the log-rank test in a plot inset. For more information about modifying the Kaplan and Meier (1958) plot in PROC LIFETEST, see ChapterĀ 23: Customizing the Kaplan-Meier Survival Plot.

FigureĀ 21.4 displays the plot. Patients in the AML-Low Risk group are disease-free longer than those in the ALL group, who in turn fare
better than those in the AML-High Risk group.

Figure 21.4: Survival Plot