CR-package {CR} | R Documentation |
This package contains R-functions to perform power calculation in a group sequential clinical trial with censored survival data and possibly unequal patient allocation between treatment and control groups. The functions 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. This package also contains R functions and methods to display the computed results.
Package: | CR |
Type: | Package |
Version: | 1.0 |
Date: | 2012-06-18 |
License: | GPL-2 |
Depends: | methods |
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.
curerate
, CureRate-class
,
showcr
, and show-methods
## 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 - follow-up 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