title: Sample size calculation for the one-sample log-rank test.
abstract: An improved method of sample size calculation for the one-sample log-rank test is provided. The one-sample log-rank test may be the method of choice if the survival curve of a single treatment group is to be compared with that of a historic control. Such settings arise, for example, in clinical phase-II trials if the response to a new treatment is measured by a survival endpoint. Present sample size formulas for the one-sample log-rank test are based on the number of events to be observed, that is, in order to achieve approximately a desired power for allocated significance level and effect the trial is stopped as soon as a certain critical number of events are reached. We propose a new stopping criterion to be followed. Both approaches are shown to be asymptotically equivalent. For small sample size, though, a simulation study indicates that the new criterion might be preferred when planning a corresponding trial. In our simulations, the trial is usually underpowered, and the aspired significance level is not exploited if the traditional stopping criterion based on the number of events is used, whereas a trial based on the new stopping criterion maintains power with the type-I error rate still controlled.
authors.affiliation: Institute of Biostatistics and Clinical Research, University of Münster, Münster, 48149, Germany.
authors.forename: René
authors.initials: R
authors.lastname: Schmidt
authors.forename: Robert
authors.initials: R
authors.lastname: Kwiecien
authors.forename: Andreas
authors.initials: A
authors.lastname: Faldum
authors.forename: Frank
authors.initials: F
authors.lastname: Berthold
authors.forename: Barbara
authors.initials: B
authors.lastname: Hero
authors.forename: Sandra
authors.initials: S
authors.lastname: Ligges
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use; D017322:Clinical Trials, Phase II as Topic / Q000379:methods*; D003198:Computer Simulation; D004359:Drug Therapy, Combination; D006801:Humans; D009447:Neuroblastoma / Q000188:drug therapy; D012107:Research Design; D018401:Sample Size; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D000972:Antineoplastic Agents, Phytogenic
keywords: one-sample log-rank test; phase-II trial; power calculation; sample size