title: A unified Bayesian semiparametric approach to assess discrimination ability in survival analysis.
abstract: The discriminatory ability of a marker for censored survival data is routinely assessed by the time-dependent ROC curve and the c-index. The time-dependent ROC curve evaluates the ability of a biomarker to predict whether a patient lives past a particular time t. The c-index measures the global concordance of the marker and the survival time regardless of the time point. We propose a Bayesian semiparametric approach to estimate these two measures. The proposed estimators are based on the conditional distribution of the survival time given the biomarker and the empirical biomarker distribution. The conditional distribution is estimated by a linear-dependent Dirichlet process mixture model. The resulting ROC curve is smooth as it is estimated by a mixture of parametric functions. The proposed c-index estimator is shown to be more efficient than the commonly used Harrell's c-index since it uses all pairs of data rather than only informative pairs. The proposed estimators are evaluated through simulations and illustrated using a lung cancer dataset.
authors.affiliation: Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, U.S.A.
authors.forename: Lili
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Biometrics Research Department, Merck Research Laboratories, U.S.A.
authors.forename: Dai
authors.initials: D
authors.lastname: Feng
authors.affiliation: Section of Thoracic Surgery, Department of Surgery, University of Michigan, Ann Arbor, Michigan, U.S.A.
authors.forename: Guoan
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, U.S.A.
authors.forename: Jeremy M G
authors.initials: JM
authors.lastname: Taylor
mesh_terms: D001499:Bayes Theorem; D015415:Biomarkers; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality; D008297:Male; D015233:Models, Statistical; D012372:ROC Curve; D012737:Sex Factors; D016019:Survival Analysis
chemical_list: D015415:Biomarkers
keywords: AUC; Concordance; Diagnostic test; Linear-dependent Dirichlet process; ROC; Time-dependent ROC; c-index