# GTSG

##### Gastrointestinal Tumor Study Group

A randomized clinical trial in gastric cancer.

- Keywords
- datasets

##### Usage

`GTSG`

##### 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.

##### 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"`

.

##### References

Moreau, T., Maccario, J., Lellouch, J. and Huber, C. (1992). Weighted log
rank statistics for comparing two distributions. *Biometrika*
**79**(1), 195--198. 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. 10.1080/03610910008813599

Tubert-Bitter, P., Kramar, A., Chal<U+00E9>, 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. 10.1016/0167-9473(94)90084-1

##### Examples

```
# NOT RUN {
## 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))
# }
```

*Documentation reproduced from package coin, version 1.3-1, License: GPL-2*