46.2.1 Epidemiology

Oral mucositis is one of the most common complications of head and neck cancer therapy and often reported by patients as the single most debilitating complication of treatment. ²⁴ Sonis et al (2003) reports that chemotherapy and/or radiation therapy (RT) may induce mucosal injury both by direct damage to epithelial cells lining the oral mucosa and also by upregulating an inflammatory response resulting in oral mucositis. ¹⁹

While risk factors may dictate the severity, almost all patients treated with RT for head and neck cancer are expected to develop some degree of oral mucositis. ^{6 , 25} Severe oral mucositis has been reported in 29 to 66% of all patients receiving head and neck RT. Increased incidence of mucositis is noted in patients with a primary tumor in the oral cavity, oropharynx, or nasopharynx, those receiving adjunctive chemotherapy, those receiving RT doses = 5,000 cGy, and those receiving altered fractionation RT. Oral mucositis has been reported to occur in approximately 20 to 40% of patients receiving conventional chemotherapy and 80% of patients receiving high-dose chemotherapy. ^{6 , 7 , 25}

46.2.2 Clinical Presentation

Oral mucositis presents as erythematous and ulcerative lesions affecting the oral mucosa. ^{1 , 19 , 25} Signs and symptoms of oral mucositis often vary throughout the progression of head and neck cancer therapy. At the beginning of head and neck RT, cumulative doses as low as 10 Gy may lead to mucosal erythema and superficial tissue sloughing. Patients may complain of discomfort and pain that is similar to a food or chemical burn, although the mucosa at this stage remains intact. As the cumulative doses increase to 20-30 Gy, the mucosa begins to break down resulting in ulcerative mucositis. At this stage, patients may report severe pain and ulcerative lesions present with uneven borders and a pseudomembrane covering, often consisting of bacterial infiltrates and necrotic tissue (▶ Fig. 41.4). This stage of severe pain may persist throughout RT and up to 3 weeks post RT.

Chemotherapy-induced ulcerative mucositis presents at earlier stages of therapy following a more acute course. The initial mucosal changes often present within 5 days of chemotherapy drug infusion and progress to the severely painful ulcerative colitis stage by day seven of therapy. The lesions may persist for 7 to 10 days and commonly heal by 3 weeks post initiation. ²⁵

46.2.3 Diagnosis and Evaluation

Multiple grading systems attempt to categorize the sequential clinical presentations of oral mucositis (▶ Table 46.1). The World Health Organization (WHO) grading system is based on the clinical presentation and patients’ functional status. Other grading systems consider the pathological changes in mucosal tissue. ^{25 , 36}

46.2.4 Anatomic Considerations and Approaches

RT and chemotherapy may lead to mucosal injuries that manifest in different locations. RT-induced mucositis is localized to the field of high-dose RT, while chemotherapy-induced mucositis may affect the entire gastrointestinal tract. ^{1 , 5 , 36} Though mucositis may affect the entire oral cavity, it commonly affects the movable mucosa (buccal mucosa, lingual mucosa, floor of the mouth, and soft palate) but rarely presents on keratinized tissue (hard palate, dorsal tongue, and gingiva). ^{1 , 25}

46.2.5 Treatment Considerations and Approaches

The Multinational Association of Supportive Care in Cancer (MASCC) recommendations are made only if strong evidence supports effectiveness in the respective treatment settings (▶ Table 46.2). Interventions that are supported with weaker evidence are also listed as suggestions in the detailed review published by MASCC and the Cochrane Group but not included in this chapter. ^{5 , 6}

46.3.1 Epidemiology

Xerostomia, the subjective sensation of dry mouth, during head and neck RT has a reported prevalence of 93%, which contrasts with the reported prevalence of 6.0% prior to the commencement of RT. ³⁷ Xerostomia is one of the most common late toxicities reported by head and neck cancer patients.

46.3.2 Clinical Presentation

Patients with decreased salivary flow often complain of xerostomia. In addition, they may present with ropey, thick saliva or complain of increased thirst. Reduced salivary flow increases the a patient’s risk for developing dental demineralization, dental decay, oral infections, dysgeusia, dysphagia, dysarthria, halitosis, oral soreness and burning, and inability to wear dentures. ^{1 – 4 , 38 , 39 , 41 , 43} The varying symptoms of hyposalivation and/or xerostomia contribute to a reduced quality of life which may affect an individual’s psychological and physical health. ^{1 – 4 , 38}

46.3.3 Diagnosis and Evaluation

Damaged salivary glands may lead to altered saliva production resulting in hyposalivation, traditionally defined as resting saliva flow rate of < 0.1 ml/minute and/or stimulated saliva flow rate of < 0.5 ml/minute. ^{20 , 21 , 43} While xerostomia is the subjective measure of dry mouth, hyposalivation serves as an objective measure for assessing salivary flow. ^{40 , 43} Xerostomia may be assessed by both patient self-reporting instruments and practitioner-observer assessments; however, patient self-reported assessments are often considered more reliable. ⁴⁰ Hyposalivation does not always correlate with the subjective symptoms of xerostomia.

46.3.4 Anatomic Considerations and Approaches

The major salivary glands (parotid, submandibular, and sublingual) are commonly included or in close proximity to target radiation fields. Parotid glands are most often irradiated in conventional RT due to their anatomical location. ^{7 , 39} In addition, serous glands are often more radiosensitive than mucus glands. ^{1 , 2}

46.3.5 Treatment Considerations and Approaches

Reversibility of reduced salivary flow is dose-limited and depends on the field of radiation. Oral health education, prevention, and care are important in maintaining a healthy dentition and preventing further dental complications in oral cancer patients. At the treatment planning stage, patients should be educated on the risks of hyposalivation and loss of protective mechanisms of saliva. Patients should be evaluated by a dentist for dental decay and infections and treated prior to RT. Further dental preventative measures include fluoride-containing mouth rinses, fluoride gels and toothpastes, over-the-counter salivary gland stimulants, sialogogues, and in some cases parasympathomimetics. ^{38 , 41 – 43} Pilocarpine hydrochloride, a parasympathomimetic, has been reported as an effective treatment for radiation-induced xerostomia; however, it may be associated with various side effects due to the parasympathetic stimulation. ^{38 , 41 , 42}

46.4.1 Epidemiology

46.4.2 Clinical Presentation

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