This option is only relevant if the "Build Current Patches Only" is checked.
If this is enabled, builds triggered with topic will be aborted when a new patch set with the same topic arrives.
If build was triggered by renaming topic the builds with old topic name will be aborted.
Be aware that manual triggers will cancel other running builds for the same topic.
Also if this option is enabled "Abort new patch sets" is not checked for changes with topic