title: A class of semiparametric transformation models for survival data with a cured proportion.
abstract: We propose a new class of semiparametric regression models based on a multiplicative frailty assumption with a discrete frailty, which may account for cured subgroup in population. The cure model framework is then recast as a problem with a transformation model. The proposed models can explain a broad range of nonproportional hazards structures along with a cured proportion. An efficient and simple algorithm based on the martingale process is developed to locate the nonparametric maximum likelihood estimator. Unlike existing expectation-maximization based methods, our approach directly maximizes a nonparametric likelihood function, and the calculation of consistent variance estimates is immediate. The proposed method is useful for resolving identifiability features embedded in semiparametric cure models. Simulation studies are presented to demonstrate the finite sample properties of the proposed method. A case study of stage III soft-tissue sarcoma is given as an illustration.
authors.affiliation: Department of Biostatistics, The University of Texas, MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 1411, Houston, TX, 77030, USA, schoi6@mdanderson.org.
authors.forename: Sangbum
authors.initials: S
authors.lastname: Choi
authors.forename: Xuelin
authors.initials: X
authors.lastname: Huang
authors.forename: Yi-Hau
authors.initials: YH
authors.lastname: Chen
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006801:Humans; D016013:Likelihood Functions; D015233:Models, Statistical; D012509:Sarcoma / Q000188:drug therapy / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000188:drug therapy / Q000601:surgery; D016019:Survival Analysis; D017741:Survivors