coin (version 1.4-3)

glioma: Malignant Glioma Pilot Study

Description

A non-randomized pilot study on malignant glioma patients with pretargeted adjuvant radioimmunotherapy using yttrium-90-biotin.

Usage

glioma

Format

A data frame with 37 observations on 7 variables.

no.

patient number.

age

patient age (years).

sex

a factor with levels "F" (Female) and "M" (Male).

histology

a factor with levels "GBM" (grade IV) and "Grade3" (grade III).

group

a factor with levels "Control" and "RIT".

event

status indicator for time: FALSE for right-censored observations and TRUE otherwise.

time

survival time (months).

Details

The primary endpoint of this small pilot study is survival. Since the survival times are tied, the classical asymptotic logrank test may be inadequate in this setup. Therefore, a permutation test using Monte Carlo resampling was computed in the original paper. The data are taken from Tables 1 and 2 of Grana et al. (2002).

Examples

## Grade III glioma
g3 <- subset(glioma, histology == "Grade3")

## Plot Kaplan-Meier estimates
op <- par(no.readonly = TRUE) # save current settings
layout(matrix(1:2, ncol = 2))
plot(survfit(Surv(time, event) ~ group, data = g3),
     main = "Grade III Glioma", lty = 2:1,
     ylab = "Probability", xlab = "Survival Time in Month",
     xlim = c(-2, 72))
legend("bottomleft", lty = 2:1, c("Control", "Treated"), bty = "n")

## Exact logrank test
logrank_test(Surv(time, event) ~ group, data = g3,
             distribution = "exact")


## Grade IV glioma
gbm <- subset(glioma, histology == "GBM")

## Plot Kaplan-Meier estimates
plot(survfit(Surv(time, event) ~ group, data = gbm),
     main = "Grade IV Glioma", lty = 2:1,
     ylab = "Probability", xlab = "Survival Time in Month",
     xlim = c(-2, 72))
legend("topright", lty = 2:1, c("Control", "Treated"), bty = "n")
par(op) # reset

## Exact logrank test
logrank_test(Surv(time, event) ~ group, data = gbm,
             distribution = "exact")


## Stratified approximative (Monte Carlo) logrank test
logrank_test(Surv(time, event) ~ group | histology, data = glioma,
             distribution = approximate(nresample = 10000))