I think you will always get topic text in the word export. You cannot disable it.
You can transfer topic text to call outs which can be disabled. Also floating topics do not appear in the Word export.
You could create a word template where the heading level styles "hide" the topic text i.e. white font, 0 pt
A MindManager macro which saves the map, deletes all topic text, exports and closes the map without saving, would solve your problem. As would one in Word which deletes all Heading style text.