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 Vol 10, No 3 (March 1996)
A Nursing Perspective on Radiation-Induced Xerostomia
Ryan R. Iwamoto, ARNP, MN
Section of Radiation Oncology, Virginia Mason Medical Center, Seattle,
Washington



Xerostomia during and following a course of head and neck irradiation
profoundly impacts the quality of life of many patients. Xerostomia not only
affects mucous membranes and teeth but also interferes with patient comfort,
nutrition, and activities of daily living. A thorough evaluation of
xerostomia is essential and should include providing anticipatory guidance
to the patient and family. In addition, education on prophylactic oral care
is necessary during the initial phases of treatment. As symptoms occur,
various palliative interventions are tailored to the patient's and family's
needs, promoting adherence to mouth care regimens and enhancing patient
comfort. Long-term follow-up with education and counseling is critical for
optimal patient management. [ONCOLOGY 10(Suppl):12-15, 1996]


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

Radiation therapy for head and neck cancer affects the salivary glands
located within the field of irradiation. When the radiation dose reaches
1,000 cGy, the patient may begin to experience mild to moderate dryness of
the mouth [1-3]. This symptom may progressively worsen over the course of
therapy and continue for more than 6 months after treatment has been
completed [4-6]. If the radiation dose 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 usual
activities of daily living (Table 1). Dryness of the mouth and lips causes
discomfort ranging from mild irritation to a severe burning sensation [8].
Due to the tenacity of the remaining saliva, managing the thick oral
secretions can be difficult, requiring the patient to expectorate frequently
or manually remove the saliva.

Eating Difficulties--The patient with xerostomia is at increased risk for
oral stomatitis and may note that the taste of foods is altered or
diminished [3,9,10]. However, the dysgeusia associated with xerostomia is
separate from the effects of radiation on the taste buds. Since saliva is a
natural lubricant used for chewing and swallowing foods, the enjoyment of
meals frequently diminishes for those with xerostomia because of
difficulties in eating. Dentures often do not fit properly in the patient
with xerostomia because saliva aids in denture stability and retention,
making it difficult to bite and chew food.

Periodontal Disease and Caries--When saliva changes from a thin to a thick,
stringy consistency, it is unable to perform its usual function of teeth
cleansing. Instead, the thick saliva causes food and bacteria to adhere to
the teeth, resulting in plaque build-up, which, in turn, leads to
periodontal disease. With prolonged xerostomia, the patient is at risk for
caries development because of the decrease in pH of the saliva and the
proliferation of cariogenic bacteria, such as Streptococcus mutans and
Lactobacillus species [9].

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

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

Sleep Disturbances--Sleep is frequently interrupted because the patient
needs to awaken to quench a parched mouth. Patients often 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 often curtail such
activities as attendance at educational lectures and recreational events
because of the inability to sit comfortably through a program. Air travel is
especially difficult because of decreased humidity in airplanes. Public
speaking can also be a problem for the patient with xerostomia; coupled with
the usual parasympathetic response one gets in front of a crowd, the person
needs to take frequent sips of water.

Exacerbating Factors--Symptoms characteristic of xerostomia may be
intensified when changes in climate occur. Areas of low humidity or use of
furnaces or heaters during cold weather can exacerbate the discomfort
associated with xerostomia.

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

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

An assessment of the oral cavity for the presence of xerostomia includes
inspection of the lips, tongue, gingiva, mucous membranes and teeth. Any or
all of the following findings may indicate xerostomia: dry, cracked lips;
furrowed or coated tongue; dry, dull appearance of the gingiva or mucous
membranes, and plaque or debris coating the teeth. Saliva may be thick,
ropy, or absent. In addition, a thorough periodontal and mouth evaluation
and prophylaxis by a 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 procedures that
will provide adequate cleansing and minimize or prevent complications, such
as stomatitis and oral infections [8,20,21]. Protocols for oral care have
been described in the literature [20,22-24].

Mouth care is recommended before and after each meal and at bedtime to
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, helping to 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 the oral cavity.
Commercial mouthwashes frequently contain alcohol and other detergents, and
therefore, should be avoided since the alcohol can cause more dryness and
produce pain when it comes into contact with inflamed mucosal tissues.

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

If dental decay occurs with daily fluoride treatments, the frequency of
application is increased to twice daily [3,19], which can also help prevent
demineralization of tooth enamel associated with xerostomia [28]. In the
presence of xerostomia, chlorhexidine mouth rinses have been used to
minimize caries development by reducing plaque formation and decreasing
levels of cariogenic bacteria in the oral cavity [29,30].

Denture Care
Xerostomia can cause the dentures to become less stable on the gingival
surface, causing tissue breakdown as a result of the increased friction
between the prosthesis and mucosa[9]. Use of denture liners can help cushion
the prosthesis; however, a thorough evaluation by the patient's dentist is
recommended to ensure denture fit and stability. Appropriate modifications
of the prosthesis improve denture retention as well as patient comfort.

Therapeutic Interventions
Saliva Substitutes and Lubricants

Commercially available saliva substitutes can be used to promote the comfort
of the mucosal surfaces. These products usually contain
carboxymethylcellulose or other lubricants, which form a slippery film on
tissues. Oral Balance was reported by radiation oncology nurses to be
well-tolerated by patients with xerostomia by providing longer-lasting
relief of dryness compared with other similar marketed products [31-33].

In addition to saliva substitutes, other lubricants can be used to provide
comfort. Less than 1 teaspoon of butter or vegetable oil placed in the mouth
has been reported to lubricate the oral cavity and provide relief of some
symptoms, although a possible disadvantage 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 glycerin is a drying agent
and the lemon can decalcify teeth as well as cause pain in a dry mouth or on
oral lesions [35,36].

Drugs

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

Dietary Modifications
Patients with xerostomia can have particular difficulties chewing and
swallowing dry or sticky foods, such as breads or peanut butter. Patients
are instructed to eat soft, moist foods. Also, the use of 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 between meals
unless contraindicated, since frequent intake of water or juices can provide
both hydration and comfort. Other remedies include applying fine mists of
water from a sprayer to dry mucosal membranes or sucking on hard, sugarless
candies or chewing gum to stimulate saliva secretion. Papain, the
proteolytic enzyme found in papayas, may be helpful in dissolving tenacious
saliva [24,41]; this suggests that patients may benefit from eating fresh
papayas or drinking papaya juice before meals.

Patient Education
Nursing care involves assessing the physical and emotional aspects of the
patient before, during, and after a course of head and neck irradiation, and
providing interventions, education, and support. Patients and families need
to know about the causes of xerostomia, its timing of occurrence, and
methods that may be used to alleviate the symptoms.

Because xerostomia may become a chronic problem, the emphasis needs to be on
long-term management of the patient's oral status. Offering support before
and during treatment is necessary but becomes even more important in the
follow-up phase of care. The patient and family may expect symptoms to
resolve quickly and may become extremely disappointed when they persist.
Helping the patient to creatively use a variety of interventions to relieve
xerostomia gives the patient and family a sense of control in minimizing 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 neck cancer and the
subsequent xerostomia that this treatment induces can be devastating to the
patient and family. Alterations in the way that the patient performs even
the most mundane activities, such as eating, can have a profound effect on a
person's coping ability [42]. Exhaustion and despair is often experienced by
the already debilitated person, since xerostomia is a 24-hour-a-day, chronic
problem.

By instructing patients and their families about the occurrence of
xerostomia, along with measures to maintain oral hygiene and treat
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 periodontal disease, can be avoided.

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