Plot conditional survival curves

library(condsurv)
library(survival)
library(ggplot2)
library(dplyr)

To plot the conditional survival curves at baseline, and for those who have survived 6 months, 1 year, 1.5 years, and 2 years, we use the gg_conditional_surv function.

The lung dataset from the survival package will be used to illustrate.

# Scale the time variable to be in years rather than days
lung2 <- 
  mutate(
    lung,
    os_yrs = time / 365.25
  )

myfit <- survfit(Surv(os_yrs, status) ~ 1, data = lung2)

cond_times <- seq(0, 2, 0.5)

gg_conditional_surv(
  basekm = myfit, 
  at = cond_times,
  main = "Conditional survival in lung data"
  )

Emily C. Zabor

Last updated: 2026-10-15