Another preventive strategy to reduce radiation-induced salivary gland hypofunction and xerostomia is surgical transfer of one submandibular gland to the submental space not included in the radiation portal in selected oropharyngeal and hypopharyngeal/laryngeal cancer patients.;[Level of evidence: I]
Amifostine is an organic thiophosphate approved for the protection of normal tissues against the harmful effects of radiation or chemotherapy, including reduction of acute or late xerostomia in patients with HNC. Studies have reported varying degrees of effectiveness.[12,13][Level of evidence: I] One randomized prospective study reported that intravenous amifostine administered during head and neck radiation therapy reduces the severity and duration of xerostomia 2 years after amifostine treatment, without apparent compromise of locoregional tumor control rates, progression-free survival, or overall patient survival.[Level of evidence: I] The intravenous administration of amifostine may cause severe adverse effects such as hypotension, vomiting, nausea, and allergic reaction. These adverse effects might be reduced by subcutaneous administration of amifostine. The possible risk of tumor protection by amifostine remains a clinical concern.
Alleviation of xerostomia
Treatment of salivary gland hypofunction and xerostomia induced by radiation therapy is primarily symptomatic. Alleviation of xerostomia includes frequent sipping or spraying of the oral cavity with water, the use of saliva substitutes, or stimulation of saliva production from intact salivary glandular tissues by taste/mastication, pharmacological sialogogues, or acupuncture.
Saliva substitutes or artificial saliva preparations (e.g., oral rinses or gels containing hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, polyglycerylmethacrylate, mucin, or xanthan gum) are palliative agents that relieve the discomfort of xerostomia by temporarily wetting the oral mucosa.
Sugar-free lozenges, acidic candies, or chewing gum may produce transitory relief from xerostomia by stimulating residual capacity of salivary gland tissue (acidic products can result in demineralization of the teeth and may not be recommended in dentate patients).
Pilocarpine is the only drug approved by the U.S. Food and Drug Administration for use as a sialogogue (5-mg tablets of pilocarpine hydrochloride) for radiation xerostomia. Treatment is initiated at 5 mg by mouth 3 times a day; the dose is then titrated to achieve optimal clinical response and minimize adverse effects. Some patients may experience increased benefit at higher daily doses; however, incidence of adverse effects increases proportionally with dose. The patient's evening dose may be increased to 10 mg within 1 week after starting pilocarpine. Subsequently, morning and afternoon doses may also be increased to a maximum 10 mg per dose (30 mg/d). Patient tolerance is confirmed by allowing 7 days between increments.