title: Sample size determination in complex clinical trials comparing more than two groups for survival endpoints.
abstract: This paper presents a sample size formula for testing the equality of kappa (> or = 2) survival distributions using the Tarone-Ware class of test statistics in the presence of non-proportional hazards, time dependent losses, non-compliance and drop-in. This method extends the derivation by Lakatos of a sample size formula for comparing two survival distributions. A sample size formula is also presented for the stratified logrank test. We describe how one can utilize these generalized formulae in calculating sample sizes and assessing power in complex multi-arm clinical trials.
authors.affiliation: Department of Preventive Medicine, School of Medicine, State University of New York at Stony Brook 11794-8036, USA.
authors.forename: S
authors.initials: S
authors.lastname: Ahnn
authors.forename: S J
authors.initials: SJ
authors.lastname: Anderson
mesh_terms: D006801:Humans; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D018401:Sample Size; D013223:Statistics as Topic; D015996:Survival Rate