Robust estimation for the Cox regression model based on trimming.

We propose a robust Cox regression model with outliers. The model is fit by trimming the smallest contributions to the partial likelihood. To do so, we implement a Metropolis-type maximization routine, and show its convergence to a global optimum. We discuss global robustness properties of the approach, which is illustrated and compared through simulations. We finally fit the model on an original and on a benchmark data set. 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.