These side effects do have different implications in the adjuvant setting than in the metastatic setting. hold therapy is definitely a consideration.
it sounds like you have tried all of the conservative management strategies, but all of the things we would typically try for xerostomia from other anti-cancer therapies might be useful. It is important to ensure that patients are getting adequate hydration in general and also implementing strategies to keep their mucous membranes moist. Sugar-free gum and hard candy can occasionally be helpful in stimulating saliva production. Dry mouth can certainly be associated with dental complications, so making sure your patient is receiving regular dental care will be important.
There are numerous saliva substitutes available for patients currently–many are over the counter and a few are available by prescription. I won’t list all of the brand names here, but I do tend to have patients try one and quickly switch to another if they are not achieving good effect. I find the sprays easier to tolerate during daytime hours, saving the gels for the evening.
Acupuncture has been shown to have some benefit in radiation induced xerostomia, so also might be something to consider.
Hope that helps,