A Nursing Perspective on Radiation-Induced Xerostomia

ABSTRACT: Xerostomia during and following a courseof head and neck irradiation profoundly impacts the quality oflife of many patients. Xerostomia not only affects mucous membranesand teeth but also interferes with patient comfort, nutrition,and activities of daily living. A thorough evaluation of xerostomiais essential and should include providing anticipatory guidanceto the patient and family. In addition, education on prophylacticoral care is necessary during the initial phases of treatment.As symptoms occur, various palliative interventions are tailoredto the patient's and family's needs, promoting adherence to mouthcare regimens and enhancing patient comfort. Long-term follow-upwith education and counseling is critical for optimal patientmanagement. [ONCOLOGY 10(Suppl):12-15, 1996]

Introduction

A common consequence of head and neck irradiation, xerostomiacan greatly diminish the patient's quality of life. The impactof xerostomia is both profound and wearing on the patient.

Radiation therapy for head and neck cancer affects the salivaryglands located within the field of irradiation. When the radiationdose reaches 1,000 cGy, the patient may begin to experience mildto moderate dryness of the mouth [1-3]. This symptom may progressivelyworsen over the course of therapy and continue for more than 6months after treatment has been completed [4-6]. If the radiationdose exceeds 4,000 cGy, xerostomia may become a chronic problem[6], and when radiation therapy is combined with chemotherapy,xerostomia may be exacerbated [7].

Impact of Symptoms

The symptoms associated with xerostomia affect the patient's usualactivities of daily living (Table 1). Dryness of the mouth andlips causes discomfort ranging from mild irritation to a severeburning sensation [8]. Due to the tenacity of the remaining saliva,managing the thick oral secretions can be difficult, requiringthe patient to expectorate frequently or manually remove the saliva.

Eating Difficulties--The patient with xerostomia is atincreased risk for oral stomatitis and may note that the tasteof foods is altered or diminished [3,9,10]. However, the dysgeusiaassociated with xerostomia is separate from the effects of radiationon the taste buds. Since saliva is a natural lubricant used forchewing and swallowing foods, the enjoyment of meals frequentlydiminishes for those with xerostomia because of difficulties ineating. Dentures often do not fit properly in the patient withxerostomia because saliva aids in denture stability and retention,making it difficult to bite and chew food.

Periodontal Disease and Caries--When saliva changes froma thin to a thick, stringy consistency, it is unable to performits usual function of teeth cleansing. Instead, the thick salivacauses food and bacteria to adhere to the teeth, resulting inplaque build-up, which, in turn, leads to periodontal disease.With prolonged xerostomia, the patient is at risk for caries developmentbecause of the decrease in pH of the saliva and the proliferationof cariogenic bacteria, such as Streptococcus mutans andLactobacillus species [9].

Oral and esophageal infections are also more common sincethe normal balance of flora in the mouth is altered, and consequently,bacterial and fungal organisms flourish [11-13]. Chronic xerostomiaalso has been shown to delay esophageal acid clearance and alter

24-hour esophageal pH--abnormalities associated with a higherincidence of gastroesophageal reflux and esophagitis [14].

Sleep Disturbances--Sleep is frequently interrupted becausethe patient needs to awaken to quench a parched mouth. Patientsoften complain either of waking up with "cotton-mouth"or with their tongue adhering to the roof of their mouth.

Effect on Other Activities--Patients with xerostomia oftencurtail such activities as attendance at educational lecturesand recreational events because of the inability to sit comfortablythrough a program. Air travel is especially difficult becauseof decreased humidity in airplanes. Public speaking can also bea problem for the patient with xerostomia; coupled with the usualparasympathetic response one gets in front of a crowd, the personneeds to take frequent sips of water.

Exacerbating Factors--Symptoms characteristic of xerostomiamay be intensified when changes in climate occur. Areas of lowhumidity or use of furnaces or heaters during cold weather canexacerbate the discomfort associated with xerostomia.

Finally, if the patient is taking medications that cause drynessof the mouth (Table 2), symptoms of xerostomia are intensified[15].

Nursing Care

Nursing interventions for xerostomia are aimed at increasing patientcomfort, maintaining mucosal integrity, preventing infections,sustaining nutrition, and increasing the tolerance of therapy(Table 3). Assessing the patient prior to treatment concerningeating, chewing, mouth-care practices, and comfort is crucial.During treatment, the mouth is routinely examined for inflammationand potential infections.

An assessment of the oral cavity for the presence of xerostomiaincludes inspection of the lips, tongue, gingiva, mucous membranesand teeth. Any or all of the following findings may indicate xerostomia:dry, cracked lips; furrowed or coated tongue; dry, dull appearanceof the gingiva or mucous membranes, and plaque or debris coatingthe teeth. Saliva may be thick, ropy, or absent. In addition,a thorough periodontal and mouth evaluation and prophylaxis bya dentist is important prior to the start of head and neck irradiation[3,12,16-19].

Mouth Care

The patient and family should be instructed about mouth-care proceduresthat will provide adequate cleansing and minimize or prevent complications,such as stomatitis and oral infections [8,20,21]. Protocols fororal care have been described in the literature [20,22-24].

Mouth care is recommended before and after each meal and at bedtimeto maintain the integrity of the oral tissues and teeth [8,25,26].Brushing with a soft-bristled toothbrush and flossing (if tolerated)clean the surfaces of the teeth and periodontal tissues, helpingto prevent or reduce plaque build-up. Also, mouth care, itself,can stimulate salivary flow[15,25].

Gargling or rinsing with normal saline every 2 hours, and as needed,reduces the stringy saliva, while cleansing and refreshing theoral cavity. Commercial mouthwashes frequently contain alcoholand other detergents, and therefore, should be avoided since thealcohol can cause more dryness and produce pain when it comesinto contact with inflamed mucosal tissues.

Caries Prevention

Fluoride treatments need to be performed at bedtime to help strengthenthe tooth enamel and prevent caries formation [27]. The fluorideis either brushed onto the teeth or put in carrier trays, whichare placed on the teeth for up to 5 minutes. The patient is instructedto not rinse the mouth or eat food or drink fluids for up to 30minutes after fluoride has been applied.

If dental decay occurs with daily fluoride treatments, the frequencyof application is increased to twice daily [3,19], which can alsohelp prevent demineralization of tooth enamel associated withxerostomia [28]. In the presence of xerostomia, chlorhexidinemouth rinses have been used to minimize caries development byreducing plaque formation and decreasing levels of cariogenicbacteria in the oral cavity [29,30].

Denture Care

Xerostomia can cause the dentures to become less stable on thegingival surface, causing tissue breakdown as a result of theincreased friction between the prosthesis and mucosa[9]. Use ofdenture liners can help cushion the prosthesis; however, a thoroughevaluation by the patient's dentist is recommended to ensure denturefit and stability. Appropriate modifications of the prosthesisimprove denture retention as well as patient comfort.

Therapeutic Interventions

Saliva Substitutes and Lubricants

Commercially available saliva substitutes can be used to promotethe comfort of the mucosal surfaces. These products usually containcarboxymethylcellulose or other lubricants, which form a slipperyfilm on tissues. Oral Balance was reported by radiation oncologynurses to be well-tolerated by patients with xerostomia by providinglonger-lasting relief of dryness compared with other similar marketedproducts [31-33].

In addition to saliva substitutes, other lubricants can be usedto provide comfort. Less than 1 teaspoon of butter or vegetableoil placed in the mouth has been reported to lubricate the oralcavity and provide relief of some symptoms, although a possibledisadvantage to this remedy is personal distaste[34].

Emollients used on the lips can help prevent drying and chafing.However, lemon-glycerin products should be avoided because glycerinis a drying agent and the lemon can decalcify teeth as well ascause pain in a dry mouth or on oral lesions [35,36].

Drugs

Several therapeutic drugs have also been used successfully totreat xerostomia. Bromhexine, anethole-trithione (Sialor, Sulfarlem),and bethanecol have all been reported to be effective in relievingxerostomia. One drug that is commercially available, pilocarpinehydrochloride, has been evaluated for its efficacy in a largenumber of patients. For example, Valdez et al [37] and Greenspanand Daniels[38] showed that pilocarpine given orally to head andneck cancer patients with radiation-induced xerostomia increasedsalivary flow and provided symptomatic relief. The safety andefficacy of oral pilocarpine tablets in successfully treatingradiation-induced xerostomia was subsequently proven in two large,placebo-controlled clinical trials involving head and neck cancerpatients [39,40].

Dietary Modifications

Patients with xerostomia can have particular difficulties chewingand swallowing dry or sticky foods, such as breads or peanut butter.Patients are instructed to eat soft, moist foods. Also, the useof gravies or sauces can help make foods easier to chew and swallow.Having ample fluids to drink with meals helps enhance eating comfort.Patients are advised to refrain from consuming alcohol or tobacco,since they can promote further mouth irritation.

Patients are also instructed to increase their fluid intake betweenmeals unless contraindicated, since frequent intake of water orjuices can provide both hydration and comfort. Other remediesinclude applying fine mists of water from a sprayer to dry mucosalmembranes or sucking on hard, sugarless candies or chewing gumto stimulate saliva secretion. Papain, the proteolytic enzymefound in papayas, may be helpful in dissolving tenacious saliva[24,41]; this suggests that patients may benefit from eating freshpapayas or drinking papaya juice before meals.

Patient Education

Nursing care involves assessing the physical and emotional aspectsof the patient before, during, and after a course of head andneck irradiation, and providing interventions, education, andsupport. Patients and families need to know about the causes ofxerostomia, its timing of occurrence, and methods that may beused to alleviate the symptoms.

Because xerostomia may become a chronic problem, the emphasisneeds to be on long-term management of the patient's oral status.Offering support before and during treatment is necessary butbecomes even more important in the follow-up phase of care. Thepatient and family may expect symptoms to resolve quickly andmay become extremely disappointed when they persist. Helping thepatient to creatively use a variety of interventions to relievexerostomia gives the patient and family a sense of control inminimizing the symptoms associated with xerostomia.

Conclusions

The presence of saliva is something most people take for granted.The experience of receiving radiation therapy for head and neckcancer and the subsequent xerostomia that this treatment inducescan be devastating to the patient and family. Alterations in theway that the patient performs even the most mundane activities,such as eating, can have a profound effect on a person's copingability [42]. Exhaustion and despair is often experienced by thealready debilitated person, since xerostomia is a 24-hour-a-day,chronic problem.

By instructing patients and their families about the occurrenceof xerostomia, along with measures to maintain oral hygiene andtreat xerostomia, nurses can help minimize these symptoms. Moreover,patients will be better able to maintain their nutritional status,and long-term side effects, such as tooth decay and periodontaldisease, can be avoided.

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