I think you need EVT_CACHE_OBJECT_PUT event for this purpose. You can always evaluate CacheEvent.oldValue to decide if the entry is new or is being updated (new entries will have old value set to null)
EVT_CACHE_ENTRY_CREATED event is fired whenever cache entry is created. This can happen, for example, when explicit lock is acquired for an entry, an entry is enlisted in transaction, etc. EVT_CACHE_OBJECT_PUT is fired when actual write to cache happens.