GTSG {coin} | R Documentation

## Gastrointestinal Tumor Study Group

### Description

A randomized clinical trial in gastric cancer.

### Usage

    GTSG

### Format

A data frame with 90 observations on 3 variables.

`time`

  survival time (days).

`event`

  status indicator for `time`: `0` for right-censored observations and `1` otherwise.

`group`

  a factor with levels `"Chemotherapy+Radiation"` and `"Chemotherapy"`.

### Details

A clinical trial comparing chemotherapy alone versus a combination of chemotherapy and radiation therapy in the treatment of locally advanced, nonresectable gastric carcinoma.

### Note

There is substantial separation between the estimated survival distributions at 8 to 10 months, but by month 26 the distributions intersect.

### Source

Stablein, D. M., Carter, W. H., Jr. and Novak, J. W. (1981). Analysis of survival data with nonproportional hazard functions. Controlled Clinical Trials 2(2), 149–159. doi: 10.1016/0197-2456(81)90005-2

### References

Moreau, T., Maccario, J., Lellouch, J. and Huber, C. (1992). Weighted log rank statistics for comparing two distributions. Biometrika 79(1), 195–198. doi: 10.1093/biomet/79.1.195

Shen, W. and Le, C. T. (2000). Linear rank tests for censored survival data. Communications in Statistics – Simulation and Computation 29(1), 21–36. doi: 10.1080/03610910008813599

Tubert-Bitter, P., Kramar, A., Chalé, J. J. and Moureau, T. (1994). Linear rank tests for comparing survival in two groups with crossing hazards. Computational Statistics & Data Analysis 18(5), 547–559. doi: 10.1016/0167-9473(94)90084-1

### Examples

    ## Plot Kaplan-Meier estimates
    plot(survfit(Surv(time / (365.25 / 12), event) ~ group, data = GTSG),
         lty = 1:2, ylab = "% Survival", xlab = "Survival Time in Months")
    legend("topright", lty = 1:2,
           c("Chemotherapy+Radiation", "Chemotherapy"), bty = "n")

    ## Asymptotic logrank test
    logrank_test(Surv(time, event) ~ group, data = GTSG)

    ## Asymptotic Prentice test
    logrank_test(Surv(time, event) ~ group, data = GTSG, type = "Prentice")

    ## Asymptotic test against Weibull-type alternatives (Moreau et al., 1992)
    moreau_weight <- function(time, n.risk, n.event)
        1 + log(-log(cumprod(n.risk / (n.risk + n.event))))

    independence_test(Surv(time, event) ~ group, data = GTSG,
                      ytrafo = function(data)
                          trafo(data, surv_trafo = function(y)
                              logrank_trafo(y, weight = moreau_weight)))

    ## Asymptotic test against crossing-curve alternatives (Shen and Le, 2000)
    shen_trafo <- function(x)
        ansari_trafo(logrank_trafo(x, type = "Prentice"))

    independence_test(Surv(time, event) ~ group, data = GTSG,
                      ytrafo = function(data)
                          trafo(data, surv_trafo = shen_trafo))

[Package coin version 1.3-0 Index]