Cache Clearing in all Web Front End Servers at once - SharePoint 2010

We Cache list Items by

HttpRuntime.Cache["CacheKey"] = datatableObj;

The caching is refreshed whenever list item is added/updated/deleted. The refreshed cache does not reflect in all
web front end servers(WFE). If user access from different WFE's, it has old cache data.

Is there a way to clear cache in all of the WFE's at once?

Thanks, B.J.Prasanna.