[R] How to get the confidence interval of area under the time dependent roc curve

[Terry Therneau]

On 04/07/2012 05:00 AM, r-help-request at r-project.org wrote:
>   It is possible to calculate the c-index for time dependent outcomes (such as disease) using the survivalROC package in R. My question is : is it possible to produce a p-value for the c-index that is calculated (at a specific point in time)?How to get the confidence interval of area under then time dependent roc curve (or by bootstrap)?
The current version of survival computes the c-index and it's standard 
error for time-dependent covariates.
Use summary(cox model fit) or the survConcordance function.

Terry T.