No, there's no difference. There's is however some types of applications where a cancel button doesn't make sense, and that's when an application requires a login. For example the admin console redirects the user directly to the login screen as you can't do anything unless you login. There's not much point in that case to show a cancel button as it would just take you back to an error screen. So the cancel button should be configurable.
That's good, since the Cancel button in the admin console does not make sense at all.
Gabriel