/* SAS code to for premutation tests to
   compare two survival functions.  Applied
   to data from the VA lung cancer trial of 
   137 male patient with inoperable lung 
   cancer.  This code is posted as 
           va.perm.sas                  */

/* Variables
     Treatment: 1=standard, 2=test (chemotherapy)
     Celltype: 1=squamous, 2=smallcell, 3=adeno, 4=large
     Survival in days
     Status: 1=dead, 0=censored
     Karnofsky score
     Months from Diagnosis
     Age in years
     Prior therapy: 0=no, 10=yes
*/
data va;
    infile 'c:\mydocuments\courses\st565\data\va.dat';
    input rx cellt time status karno months age prior_rx;

    prior_rx = prior_rx/10;

    if (cellt=1) then celltype= 'squamous';
    if (cellt=2) then celltype= 'smallcell';
    if (cellt=3) then celltype= 'adeno';
    if (cellt=4) then celltype= 'large';

proc lifetest method=KM plots=(s) graphics 
 outs=su data=va;
 time time*status(0);
 strata rx;
 symbol1 v=none color=black line=1 w=3;
 symbol2 v=none color=black line=2 w=3;
run;

%include "c:\mydocuments\courses\st565\sas\randgen.macro.sas";
%include "c:\mydocuments\courses\st565\sas\test.macro.sas";


%RAND_GEN(indata=va, time=time, cens=status,
          numreps=1000, group=rx, seed=0);

%TEST(time=time, cens=status, censval=0,
      test=logrank, group=rx, type=rand);

%TEST(time=time, cens=status, censval=0,
      test=gehan, group=rx, type=rand);