Hello STATA Community,

I am currently using version 15.1 of STATA.

I have some straightforward survival time data, (time in years, censor (1=failed, 0=censored) , group of interest). example as follows:

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input double pfsyrs byte pfscensor str17 first_deftx_type
   4.802739726027397 1 "RT"     
   3.147945205479452 0 "Surgery"
                   0 0 "RT"     
   1.704109589041096 0 "RT"     
  4.5698630136986305 0 "RT"     
   3.734246575342466 0 "Surgery"
  3.2246575342465755 0 "Surgery"
   7.043835616438356 0 "Surgery"
   4.816438356164384 0 "Surgery"
   1.189041095890411 0 "Surgery"
   .6958904109589041 0 "Surgery"
   -.273972602739726 0 "RT"     
  .15616438356164383 0 "RT"     
  2.1890410958904107 0 "RT"     
  .11232876712328767 1 "Surgery"
   .4986301369863014 1 "RT"     
-.052054794520547946 0 "RT"     
  11.734246575342466 0 "RT"     
                   0 1 "Surgery"
  11.542465753424658 0 "RT"     
  12.126027397260273 0 "RT"     
   4.594520547945206 0 "RT"     
  1.6383561643835616 0 "RT"     
   .3863013698630137 1 "Surgery"
                   0 1 "RT"     
   .8493150684931506 1 "RT"     
  1.6821917808219178 1 "RT"     
   7.682191780821918 0 "RT"     
   .8712328767123287 0 "RT"     
  1.4712328767123288 0 "Surgery"
   1.515068493150685 0 "Surgery"
  1.1863013698630136 0 "Surgery"
   4.183561643835616 1 "RT"     
   10.35068493150685 0 "RT"     
  2.6082191780821917 1 "RT"     
   .6520547945205479 0 "Surgery"
  3.4547945205479453 0 "RT"     
   .1178082191780822 1 "Surgery"
   .8246575342465754 1 "Surgery"
  3.0027397260273974 0 "Surgery"
   .7068493150684931 0 "Surgery"
   2.802739726027397 0 "Surgery"
   4.561643835616438 1 "RT"     
    8.24931506849315 0 "RT"     
                 -.4 0 "RT"     
  .23835616438356164 0 "RT"     
 -.03287671232876712 0 "RT"     
  2.8054794520547945 0 "RT"     
  1.5068493150684932 0 "RT"     
   5.175342465753425 0 "Surgery"
  1.9205479452054794 0 "Surgery"
end
I can easily display the 5 and 10 year survival point estimates for the groups using the "sts list" command:

Code:
. stset pfsyrs, failure(pfscensor) scale(1)

     failure event:  pfscensor != 0 & pfscensor < .
obs. time interval:  (0, pfsyrs]
 exit on or before:  failure

------------------------------------------------------------------------------
      4,929  total observations
        568  observations end on or before enter()
------------------------------------------------------------------------------
      4,361  observations remaining, representing
      1,012  failures in single-record/single-failure data
 15,887.025  total analysis time at risk and under observation
                                                at risk from t =         0
                                     earliest observed entry t =         0
                                          last observed exit t =  89.83836



. sts list, by(first_deftx_type) failure at(5 10)

         failure _d:  pfscensor
   analysis time _t:  pfsyrs

              Beg.                      Failure       Std.
    Time     Total     Fail             Function     Error     [95% Conf. Int.]
-------------------------------------------------------------------------------
RT 
       5       442       51              0.0686    0.0097     0.0520    0.0903
      10       147       28              0.1511    0.0180     0.1194    0.1902
Surgery 
       5       800       95              0.0577    0.0061     0.0468    0.0711
      10       235       45              0.1550    0.0155     0.1272    0.1883
-------------------------------------------------------------------------------
Note: Failure function is calculated over full data and evaluated at indicated
      times; it is not calculated from aggregates shown at left.

However, what I would like to do is actually just save the value of the 5-year failure function for any particular group (in this case, for the "RT" group it is equal to 0.0686) as a local scalar so that I can use this discrete value in a program. Does anyone know how to save a failure function value from a discrete specified time (like 5 years) for a KM estimate in a local scalar?

Many Thanks,

Jonathan Tward