Diagnosis, Prevention, and Treatment of Radiotherapy-Induced Xerostomia: A Review

Abstract

In patients with head and neck cancer, irradiation (IR)-sensitive salivary gland (SG) tissue is highly prone to damage during radiotherapy (RT). This leads to SG hypofunction and xerostomia. Xerostomia is defined as the subjective complaint of dry mouth, which can cause other symptoms and adversely affect the quality of life. In recent years, diagnostic techniques have constantly improved with the emergence of more reliable and valid questionnaires as well as more accurate equipment for saliva flow rate measurement and imaging methods. Preventive measures such as the antioxidant MitoTEMPO, botulinum toxin (BoNT), and growth factors have been successfully applied in animal experiments, resulting in positive outcomes. Interventions, such as the new delivery methods of pilocarpine, edible saliva substitutes, acupuncture and electrical stimulation, gene transfer, and stem cell transplantation, have shown potential to alleviate or restore xerostomia in patients. The review summarizes the existing and new diagnostic methods for xerostomia, along with current and potential strategies for reducing IR-induced damage to SG function. We also aim to provide guidance on the advantages and disadvantages of the diagnostic methods. Additionally, most prevention and treatment methods remain in the stage of animal experiments, suggesting a need for further clinical research, among which we believe that antioxidants, gene transfer, and stem cell transplantation have broad prospects.

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“…The patient's response to radiation therapy is individual and depends on the radiation dose and treatment area. Radiotherapy contributes to short-term dryness or total lack of salivary production [18] .…”

Treatment Complications of Head and Neck Cancers and Rehabilitation Measures: A Narrative Review

“…Some studies have found that drinking water frequently can be as effective as using saliva substitutes. Mucoadhesive discs of xylitol or sugar-free gum have been used with varying results [83][84][85][86][87][88].…”

“…In recent years, clinically validated dose constraints have been established for salivary-associated OARs, such as parotid glands, submandibular glands, and oral cavities. With the introduction of IMRT, oncologists could use an inverse planning algorithm and multiple fields to spare OARs from toxic threshold doses [ 87 , 88 ].…”

Investigation of Hydrocolloid Plant Polysaccharides as Potential Candidates to Mimic the Functions of MUC5B in Saliva

“…Other clinical investigations demonstrated that radiation therapy in the head-neck area leads to the disruption of the mucin micro-network of saliva [17]. As a result, the water-retention and adhesive functions of saliva are weakened or lost, contributing to the development of xerostomia (i.e., dry mouth) and oral mucositis [18,19].…”

“…The state-of-the-art therapeutic interventions to reduce dry mouth or slow down the development of oral mucositis are topical treatments, such as saliva-replacement fluids or gels containing polysaccharides, such as carboxy-methylcellulose, glycerol, or polyethylenoxide; xanthan gum; or mucins [20][21][22]. However, several studies have shown that the effect of most marketed saliva substitutes is limited [14,19,23,24]. The disadvantages include a short duration of action, an unpleasant feeling in the mouth, or a limited effect on the prevention of enamel and dentin demineralization [14,19,25].…”