A joint frailty-copula model between tumour progression and death for meta-analysis

Dr Virginie Rondeau will present the Department of Statistical Sciences seminar with a talk entitled, A joint frailty-copula model between tumour progression and death for meta-analysis".  

Dr Rondeau is a researcher in Biostatistics at INSERM, Université Bordeaux. She obtained Ph.D. in Biostatistics from Université Victor Segalen in 2000. Her research interests are prognostic survival models and validation, joint models for recurrent events and death, recurrences of cancer (follicular lymphomas, breast cancer, colorectal).

Dependent censoring often arises in biomedical studies when time to tumour progression (e.g., relapse of cancer) is censored by an informative terminal event (e.g., death). For meta-analysis combining existing studies, a joint survival model between tumour progression and death has been considered under semicompeting risks, which induces dependence through the study-specific frailty. Our paper here utilizes copulas to generalize the joint frailty model by introducing additional source of dependence arising from intra-subject association between tumour progression and death. The practical value of the new model is particularly evident for meta-analyses in which only a few covariates are consistently measured across studies and hence there exist residual dependence. The covariate effects are formulated through the Cox proportional hazards model, and the baseline hazards are nonparametrically modeled on a basis of splines. The estimator is then obtained by maximizing a penalized log-likelihood function. We also show that the present methodologies are easily modified for the competing risks or recurrent event data, and are generalized to accommodate left-truncation. Simulations are performed to examine the performance of the proposed estimator. The method is applied to a meta-analysis for assessing a recently suggested biomarker CXCL12 for survival in ovarian cancer patients. We implement our proposed methods in R joint.Cox package

Wednesday, February 8, 2017 - 13:00

Lecture Theatre 3, PD Hahn.  Upper Campus, UCT