Agree - except for those that have had extensive surgical resection (for instance part or all of tongue removed, as well as some or all of soft palate) and still have limited function (can't talk well, can't swallow anything, can't even hack up phlegm very well, etc...) - it may be difficult to do the swish and spit without trouble. Some HNSCC patients post surgery can never swallow hardly anything ever again, and if they try, they run the risk of it going into the lungs and they can get aspiration pneumonia or such. IV would probably be more convenient for those patients - who will likely be a minority (mercifully).