format
ll{
trt: 1=standard 2=test
celltype: 1=squamous, 2=smallcell, 3=adeno, 4=large
time: survival time
status: censoring status
karno: Karnofsky performance score (100=good)
diagtime: months from diagnosis to randomisation
age: in years
prior: prior therapy 0=no, 1=yes
}source
Kalbfleisch and Prentice "The Statistical Analysis of Failure Time Data"