Description Usage Arguments Details Value Author(s) References See Also Examples
This R-function performs power calculation in a group sequential clinical trial with censored survival data and possibly unequal patient allocation between treatment and control groups. The function can also be used to determine the study duration in a clinical trial with censored survival data as the sum of the accrual duration, which determines the sample size in a traditional sense, and the follow-up duration, which more or less controls the number of events to be observed.
1 2 | curerate(rho = 0, numreps, cureobs, curerx, medobs, medrx, acrate, probrx,
actime, futime, info, crits, alpha = 0.025)
|
rho |
numeric specifying the value of rho in the G-rho test (Harrington and Fleming, 1982), rho=0 (default) gives the log-rank test, rho=1 the Peto-Peto Wilcoxon test, and rho=-1 the test discuss by Gray and Tsiatis, 1989. |
numreps |
integer > 0 specifying the number of replications. |
cureobs |
numeric specifying the probability of cure on the observation arm of the study. |
curerx |
numeric specifying the probability of cure on the treatment arm of the study. |
medobs |
numeric > 0 specifying the median survival among the non-cured on observation. |
medrx |
numeric > 0 specifying the median survival among the non-cured on treatment. |
acrate |
numeric > 0 specifying the rate at which patients accrue, combined over both observation and treatment arms of the study. |
probrx |
numeric specifying the probability of assigment to the treatment arm, must be in [0,1]. |
actime |
vector specifying the accrual durations. |
futime |
vector specifying the follow-up durations. |
info |
vector of information times for the interim looks; must be an increasing sequence in (0,1]. |
crits |
vector of critical values corresponding to the interim analysis time points
specified in |
alpha |
numeric specifying the one-sided level of significance; must be in (0,1);
default value |
The function curerate
is used to calculate the power of weighted log-rank
tests in cure rate models.
An object of S4 class CureRate
which has the following 22 components
cureobs |
numeric |
medobs |
numeric |
curerx |
numeric |
medrx |
numeric |
actime |
numeric vector |
futime |
numeric vector |
info |
numeric vector |
crits |
numeric vector |
alpha |
numeric |
rho |
numeric |
acrate |
numeric |
probrx |
numeric |
numreps |
integer |
numobs |
numeric matrix |
timept |
numeric 3D array |
deaths |
numeric 3D array |
testname |
character |
power |
numeric 3D array |
numobs |
numeric matrix |
indac |
vector of integers |
indfu |
vector of integers |
printflag |
integer |
Emil A. Cornea, Bahjat F. Qaqish, and Joseph G. Ibrahim
Maintainer: Emil A. Cornea <ecornea@live.unc.edu>
Ewell, M. and Ibrahim, J.G. (1997). The Large Sample Distribution of the Weighted Log Rank Statistic Under General Local Alternatives. Lifetime Data Analysis,3,5-12
Kim, K. (1992). Study Duration for Group Sequential Clinical Trials with Censored Survival Data Adjusting for Stratification. Statistics in Medicine, Vol. 11, 1477-1788
Harrington, D. P. and Fleming, T. R. (1982). A class of rank test procedures for censored survival data. Biometrika 69, 553-566.
Gray, R.J. and Tsiatis, A.A. (1989). A linear rank test for use when the main interest is in differences in cure rates. Biometrics 45, 899-904.
CR-package
, CureRate-class
,
showcr
, and show-methods
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | ##---- Should be DIRECTLY executable !! ----
## Input Data
################
# rho - specifies the value of rho in the G-rho test (Harrington and Fleming, 1982).
# rho = 0 gives the logrank test, and rho = 1 the Peto-Peto Wilcoxon test
#(and rho = -1 the test discussed by Gray and Tsiatis, 1989).
rho = 0
numreps = 500
##cureobs - probability of cure on the observation arm of the study
cureobs = .359
##curerx - probability of cure on the treatment arm of the study
curerx = .459
##medobs - median survival among the non-cured on observation
medobs = .747
##medrx - median survival among the non-cured on treatment
medrx = .859
##acrate - rate at which patients accrue, combined over both
##observation and treatment arms of the study
acrate = 232
##probrx - probability of assignment to the treatment arm
probrx = .5
##actime - accrual duration
actime = c(3.3, 3.5, 3.8);
##futime - followup duration
futime = c(2.0, 2.5)
##info - vector of information times for the interim looks
##must be an increasing sequence in (0,1]
info = c( .35, .61, .86, 1.0)
##crits - vector of critical values corresponding to the
##interim analysis time points specified in info
crits = c(3.6128, 2.6506, 2.1894, 2.0536)
#############################################################
### Log-rank test: rho=0 (default)
mycr<-curerate(rho,numreps,cureobs,curerx,medobs,medrx,acrate,
probrx,actime,futime,info,crits)
mycr ### (*)
show(mycr) ### same as above
showcr(mycr) ### same as above
showcr(mycr,full.result=TRUE)
showcr(mycr,indac=2,indfu=1)
showcr(mycr,indac=2:3,indfu=2:1)
showcr(mycr,indac=c(1,3),indfu=2)
show(mycr) ### same as (*) above
showcr(mycr) ### same as above
mycr ### same as above
### Peto & Peto modification of the Gehan-Wilcoxon test: rho=1
rho=1
mycr<-curerate(rho,numreps,cureobs,curerx,medobs,medrx,acrate,
probrx,actime,futime,info,crits)
mycr
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