survival (version 3.5-8)

hoel: Mouse cancer data

Description

Days until occurence of cancer for male mice

Usage

data("cancer")

Format

A data frame with 181 observations on the following 4 variables.

trt

treatment assignment: Control or Germ-free

days

days until death

outcome

outcome: censor, thymic lymphoma, reticulum cell sarcoma other causes

id

mouse id

Details

Two groups of male mice were given 300 rads of radiation and followed for cancer incidence. One group was maintained in a germ free environment. The data set is used as an example of competing risks in Kalbfleisch and Prentice. The germ-free environment has little effect on the rate of occurence of thymic lymphoma, but significantly delays the other causes of death.

References

Hoel, D.G. (1972), A representation of mortality data by competing risks. Biometrics 33, 1-30. Kalbfleisch, J.D. and Prentice, R.L. (1980). The statistical analysis of failure time data.

Examples

hsurv <- survfit(Surv(days, outcome) ~ trt, data = hoel, id= id)
plot(hsurv, lty=1:2, col=rep(1:3, each=2), lwd=2, xscale=30.5,
      xlab="Months", ylab= "Death")
legend("topleft", c("Lymphoma control", "Lymphoma germ free",
                    "Sarcoma control", "Sarcoma germ free",
                    "Other control", "Other germ free"),
       col=rep(1:3, each=2), lty=1:2, lwd=2, bty='n')
hfit <- coxph(Surv(days, outcome) ~ trt, data= hoel, id = id)