You can invalidate ASP.NET output level cache using cache dependencies.
The ASP.NET webform should contain something like this:
<%@ OutputCache Duration="60" Location="Server" VaryByParam="None" %>
If you need to invalidate the cache prior to the 60 seconds elapsing you can do this by setting up a cache dependency between the page and an item in the cache:
Now, when the "MyCachedData" cachekey is changed or invalidated the cached page is invalidated too.