Nutritional Implications of Dental and Swallowing Issues in Head and Neck Cancer

Introduction

Worldwide, a half million new cases of head and neck cancer arise each year.[1] In the United States, head and neck tumors account for approximately 4% of the overall incidence of cancer, and represented approximately 30,750 new cases in 1997.[1]

Cancers of the mouth, larynx, pharynx, tongue, and salivary glands have an enormous impact on eating and swallowing. The location or progression of the tumor itself causes various dental, swallowing, and nutritional consequences, as do such treatments as surgery, radiation, and chemotherapy. Moreover, common side effects of cancer treatment, such as xerostomia, mucositis, dental caries, taste alterations, and dysphagia, may give rise to secondary malnutrition. Strategies for the prevention and alleviation of such problems include dental, swallowing, and nutritional therapies. Therefore, optimal patient care requires a multidisciplinary approach involving dental, speech, and nutritional professionals.

This article discusses therapies used in managing dental and swallowing problems experienced by head and neck cancer patients. In addition, it provides guidelines for integrating dental, swallowing, and nutritional interventions into overall patient management both before cancer treatment is initiated (Table 1) and during and after treatment (Table 2). This paper also aims to expand health professionals’ knowledge of dental and swallowing therapies in the head and neck cancer patient population.

Nutritional Issues in Head and Neck Cancer

Over half of patients with head and neck cancer are malnourished.[2,3] Their nutritional status is often compromised even before the diagnosis of cancer is made and treatment is initiated. Weight loss and dysphagia are early signs of head and neck cancer, often prompting the patient to seek medical attention.

Early screening and assessment help determine the degree of malnutrition present and which nutritional intervention is needed. The assessment should include information on acute and chronic weight loss, current laboratory data, and clinical observation. A history of patients’ dietary intake, both at home and during hospitalization, provides an estimate of the adequacy of calorie, protein, and fluid intake. The degree of feeding impairment and swallowing difficulties anticipated during and after treatment also should be estimated so as to make recommendations about oral, enteral, and parenteral therapies that may be necessary.

Treatment of the head and neck cancer patient is unique in that the procedures and therapies used (ie, surgery, radiation, and chemotherapy) may have a direct effect on the oral structures and, therefore, can impair chewing, swallowing ability, and nutritional status. Nutritional intervention should be an integral part of pretreatment and posttreatment patient care, as it may improve patient prognosis and decrease the likelihood of secondary malnutrition.

Typical nutritional interventions provided include various strategies to overcome the side effects of cancer treatment (Table 3). For example, increasing fluid intake helps relieve xerostomia. Patients who are underweight or losing weight may need to eat more frequently; also, oral nutritional supplements can help patients maintain adequate calorie and protein intake. Nutritional support, including enteral and parenteral routes, may be indicated for patients who cannot meet their nutritional needs by mouth. Also, if dysphagia is present, modification of food textures and consistencies may be required.

Since nutritional risks are high in head and neck cancer patients, nutritional therapy is a critical part of their care. In addition to the factors that contribute to malnutrition in all cancer patients, dental and swallowing problems are of special concern in head and neck cancer patients. In order to formulate an appropriate nutritional care plan for these patients, consideration should be given to dental and swallowing problems that may be contributing to declining nutritional status.

Dental and Oral Problems

Dental treatment and oral health are essential for the comprehensive care of head and neck cancer patients. The dentist and dental hygienist can help the patient with oral and dental problems and assist in instituting preventive measures. All patients need pretreatment and posttreatment education to decrease the risk of dental caries. They also need special instruction on oral hygiene (ie, brushing, flossing, rinses, and other plaque removal devices). Therefore, early dental referral is necessary. Improved oral health can have a beneficial impact on chewing and swallowing ability.

In particular, a dental consultation should be initiated before radiation therapy in head and neck cancer patients. Even patients with excellent oral health need to be informed of the dental risks of radiation (see below), especially if they do not use fluoride daily.

Problems Secondary to Radiation and Chemotherapy

Many oral problems result from radiation therapy. If left untreated, these radiation-induced problems can have a negative effect on patient outcome and recovery. Acute reactions associated with radiation therapy to the head and neck usually occur 10 to 17 days into treatment[4] but can begin as early as the first week. These reactions, which include dental caries, xerostomia, oral mucositis, and bacterial and fungal infections, are a result of damage to the salivary glands (parotid, sublingual, and submandibular glands) and the consequent reduction in saliva production.

 The effects of chemotherapy are similar to those of radiation treatment. Problems that may occur include mucositis, fungal infections, xerostomia, throat and mouth pain, taste changes, food aversions, nausea, and diarrhea. The kind of side effects that a person may experience depend on the kind of chemotherapy drugs used, as well as the dose and frequency of the treatments. Some side effects can be prevented (eg antinausea medications) or at least effectively managed (see Table 3 and Table 4).

Functionally, saliva balances the microbial flora in the mouth and maintains an appropriate acid-base medium. Saliva lubricates the mouth and aids in chewing, swallowing, and digesting food. In addition, saliva provides substances with antibacterial, antifungal, and antiviral activity, and protects the oral mucosa against physical and thermal trauma, toxins, and chemicals.[5,6] Salivary proteins help maintain a balance of calcium and phosphate ions, which aid in tooth remineralization.[5]

Table 4 summarizes the treatments available for oral complications of radiation and chemotherapy. These treatments can alleviate pain and ease eating and swallowing. Dental therapy for various side effects of radiation and chemotherapy includes prescription of fluoride application, saliva-stimulating medications, and antifungal and antibacterial agents, as well as frequent dental cleanings.

Prevention/Treatment of Radiation Caries--Radiation caries is a major problem in patients undergoing radiation therapy to the head and neck. The effectiveness of topical fluoride treatment in halting radiation caries has been examined in head and neck cancer patients. Most patients treated with fluoride maintained good dental status while following the treatment regime, which included use of a fluoride gel in a custom-made tray.[7] However, if patients discontinued fluoride treatment, caries occurred after 3 to 6 months.[7] In addition to decay prevention, fluoride gel can minimize tooth sensitivity.

The daily use of fluoride is therefore critical in patients undergoing radiation therapy. A custom-made mouth tray should be fabricated by a dentist prior to radiation therapy. Instructions on fluoride application (Table 5) should be given in both written and verbal forms.[8]

Prevention of dental caries also includes counseling on avoiding foods high in sugar. Sometimes, in patients who cannot tolerate fat, high-sugar foods and liquids may be recommended to increase caloric intake. In order to decrease dental risks, it is critical that these patients be advised to brush and floss immediately after eating.

Treatment of xerostomia is also critical in the management of head and neck cancer patients. Sugar-free mints and gum can be used to help stimulate saliva. Artificial saliva is also effective in relieving xerostomia; however, one study indicated that water can also help the mouth stay lubricated.[9] In addition, cost was identified as a deterrent to the use of saliva substitutes.[9]

Another method of treating xerostomia is to induce salivary flow medically. Pilocarpine(Drug information on pilocarpine) hydrocloride (Salagen) stimulates the cells of the salivary glands that are not totally damaged by radiation. Side effects of pilocarpine hydrochloride include sweating, headache, rhinitis, dizziness, and urinary frequency.

Treatment of Mucositis--Mucositis can be treated in a variety of ways. These include topical anesthetics, diphenhydramine(Drug information on diphenhydramine) solution, water, saline, or sodium bicarbonate(Drug information on sodium bicarbonate) solution.[10] Vitamin E(Drug information on vitamin e) capsules can lubricate the oral mucosa and are highly acceptable to patients due to their lack of toxic effects. In one study of patients with chemotherapy-induced mucositis, topical application of vitamin E was effective in healing the mucosa.[11] Whether the effects of vitamin E are due to some action of the vitamin or simply to increased lubrication remains to be determined.

Preliminary studies of capsaicin (the active ingredient in chili peppers) showed that a capsaicin-containing candy provided some relief of oral mucositis.[12] Also, a calcium phosphate(Drug information on calcium phosphate) rinse is being used to alleviate mucositis in some institutions; however, there are limited data on its effectiveness.

Alcohol(Drug information on alcohol)-containing mouth rinses dry the oral mucosa and are contraindicated in patients with mucositis. Hydrogen peroxide(Drug information on hydrogen peroxide) solutions should also be avoided because of their ability to break down new tissue.[6] A soft diet may be recommended for patients with mucositis, to prevent further tissue irritation.

Long-Term Oral Side Effects--Long-term oral side effects associated with radiation therapy include osteoradionecrosis and trismus. In patients with osteoradionecrosis, bone death occurs primarily because of vascular insufficiency to the area. This condition can be very painful for patients and sometimes results in eventual loss of portions of the maxilla or mandible.[8] Osteoradionecrosis tends to occur in persons who have chronic, advanced periodontal disease.

If osteoradionecrosis does occur, treatment involves gentle debridement with salt and soda rinses, antibiotics, and hyperbaric oxygen therapy. [8] Hyperbaric oxygen therapy is used to prevent the initiation of bone necrosis and to prevent its further progression. It is generally accepted that a patient with bone exposure that persists for longer than 6 months without any improvement would be a candidate for hyperbaric oxygen therapy.[8]]

Trismus (fibrosis of oral muscles) makes chewing foods difficult. It can be minimized or eliminated with appropriate jaw exercises.