hi all,
I am using Stat 16 on Mac.
I am calculating Kaplan Meier survival curves for 2 groups of patients who do or do not have a genetic mutation.
But after I set the survival data (stset), I am getting what seems like an error in my descriptive statistics for the survival data.
Ex: nothing listed for 25%, 50%, 75% survival times.
Is this because my failure rate is low compared to the time at risk?
Is there any way around this to determine the median survival time for each group?
Thank you!

stsum, by(hyper)

failure _d: recur2 == 1
analysis time _t: betweendx2censor

| Incidence Number of |------ Survival time -----|
hyperm~h | Time at risk rate subjects 25% 50% 75%
---------+---------------------------------------------------------------------
No | 352,899 .0000878 260 . . .
Yes | 87,166 .0001262 63 1943 . .
---------+---------------------------------------------------------------------
Total | 440,065 .0000954 323 . . .