This should not make any difference what so ever as clearing the cache only removes temp files and old files that you have adjusted. Save files should not be touched and they can't even be touched by the cache. These problems are not related to each other.
Stated on the xbox FAQ is :
The most important part of clearing the cache is knowing what to
expect. All downloaded game updates will be removed. So if you have
downloaded an auto-update for a game, in order to play it on Xbox Live
you will need to re-download it.
**** User game saves, profiles, demos, videos, etc. are not deleted during
Note the last sentence.
This however does unfortunately mean that if you cant seem to get to your save file in the minecraft world it has been lost. My guess would be that something went wrong while re-downloading the updates and that during that process your save file got corrupted. Minecraft then automatically fixes that but in your case that meant that it created a whole new .world map.