Oral Implications of Cancer Treatment

The number of deaths caused by cancer are on a downward trend.¹ Data gathered in 2001 found that approximately 68.3% of patients with cancer survived 5 years, and this percentage continues to increase.¹ Unfortunately, the overall survival rates for oral and pharyngeal cancer have not improved significantly over the past 30 years because of late detection and tumor metastasis.¹ In 2010, there were approximately 36,500 new cases of oral cavity and pharynx cancer and 7,880 deaths.²

The best way to improve survival rates is early detection, treatment, and education. As dental hygienists, our responsibility is early detection of head and neck cancer through intraoral and extra oral examination, including a visual exam of the skin at every appointment and education of early signs of change. A secondary responsibility is to participate as a member of the oncology team. This includes oral care and patient education prior to and following oncology treatment.

Once cancer is diagnosed, patients and their families are presented with many treatment options. The stress of deciding on a treatment plan in addition to the emotional upheaval caused by a cancer diagnosis make this a very difficult time for cancer patients. An oncology team can substantially reduce patients’ emotional turmoil and assist in explaining treatment plan options.

Before cancer therapy begins, an initial dental visit is needed to address pre-existing conditions that could lead to complications. The goal of the pretreatment dental examination is to improve the patient’s quality of life by reducing the risk and severity of oral complications; preventing, eliminating, or reducing oral pain; preventing or reducing incidence of subsequent bone necrosis; and provide support to the patient and family.³ This examination may decrease higher treatment and supportive care costs.

CANCER THERAPY

Treatment for cancer is determined by the cancer type, cell type, and staging of the tumor. After the initial biopsy, the treatment may include a single modality or a combination of several therapies. Treatment may include surgery, chemotherapy, radiation, bone marrow and blood transplantation, hormone therapy, and immunotherapy. The oncologist’s goal for treatment is removal or elimination of the malignant cells. Unfortunately, normal healthy cells are destroyed in the process. Many patients who undergo cancer therapy will experience oral complications that may delay or prevent the delivery of optimal therapy. This is where the oral health evaluation prior to treatment may eliminate psychological stress and help prevent serious complications.

Surgery is the treatment of choice if the tumor is of small size (early stage I and II). The decision is made on the basis of the tumor’s site and size, histologic findings, the patient’s wishes, and advice of the medical team.⁴

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TABLE 1. NORMAL COMPLETE BLOOD COUNT³

• Red blood cell count 4.2 million/mm³ to 6.0 million/mm³
• White blood cell count 4,000/mm³ to 11,000/mm³
• Hemoglobin 12g/dL to 18g/dL
• Hematocrit 36% to 52%
• Platelet count 150,000/mm³ to 450,000/mm³

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Chemotherapy is a drug that is administered systemically over several weeks or months in a sequence with the goal of killing the tumor cells. Chemotherapy may also be used as an adjunctive therapy with radiation therapy and prior to bone marrow transplantation. Chemotherapy is often toxic to other rapidly dividing cells, such as bone marrow, hair, and mucosa of the oral cavity, epithelium, and gastrointestinal (GI) tract.⁵ This toxicity may result in mucositis and ulceration of the oral cavity.

Mucositis is the primary reason that patients need to stop chemotherapy (see Figure 1). Inflammation and ulceration of the mucous membranes in the mouth, pharynx, esophagus, and GI tract can increase risk of pain, oral and systemic infection, and compromised nutrition. Severity of mucositis is directly related to neutropenia, which is the abnormal decrease in neutrophils (white blood cells). Decreased platelet numbers are also a common complication. The oncologist should be consulted if dental treatment is needed during chemotherapy cycles. Important information includes clotting factors, absolute neutrophil count, and presence of an indwelling central venous catheter, which may necessitate premedication. Table 1 provides normal blood count numbers.³

Radiation to the oropharyngeal area for malignant tumors, lymphomas, or leukemia may be administered for 3 weeks to 7 weeks with dosage of 30 Gray (Gy) to 70 Gy, dependent on tumor size. Radiation affects only those tissues directly within the therapy field. This eliminates oral complications when radiation is administered to areas other than the oral cavity and/or salivary glands.

Factors that may influence the intensity and duration of oral manifestations during radiation therapy include: fraction size; field of radiation; total dose; previous surgical intervention; rate of radiation delivery; oral, medical, and nutritional status of patient; and history of tobacco and alcohol use.⁵ Table 2 provides a list of potential oral manifestations of radiation therapy applied to the oropharyngeal and salivary gland region.

Hematopoietic stem cell transplantation has become more common in the treatment of hematologic diseases including leukemia, aplastic anemia, lymphoma, and some solid tumors. The bone marrow is intentionally destroyed by high dose chemotherapy, with or without radiation therapy. The goal is for the bone marrow to be restored by the infusion of new bone marrow or peripheral cells that are either the patient’s own (autologous), from a family member, from a matched unrelated donor (allogeneic), or from an identical twin (syngeneic).

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TABLE 2. POTENTIAL ORAL MANIFESTATIONS OF RADIATION THERAPY APPLIED TO THE OROPHARYNGEAL AND SALIVARY GLAND REGION.

Acute

• Mucositis/ulceration/pain
• Taste alterations
• Salivary gland dysfunction
• Infection
• Nutritional deficiency

Chronic

• Salivary gland dysfunction
• Radiation caries and demineralization
• Trismus/temporomandibular disorders
• Soft tissue necrosis
• Osteoradionecrosis

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The patient is at risk of developing significant oral sequelae during initial phases of the transplant including oral mucositis and ulceration; hemorrhage; infections (fungal, viral, and bacterial); and xerostomia. Transplantation or engraftment takes place within 2 weeks to 4 weeks when the cells begin to reproduce new marrow and the acute oral complications begin to resolve.

Acute or chronic graft-versus host disease (GVHD) may develop for allogeneic transplant patients, which may cause significant immunosuppression. Associated GVHD complications include mucositis; mucosal atrophy; ulcerations; oral infections, including candidiasis (see Figure 2); immune-related complications, including lichenoid reactions; scleroderma (presenting as a lacey pattern); lupus-like changes (limited oral opening and tongue mobility); and xerostomia with rampant dental breakdown.⁶ All sources of oral infection need to be addressed before transplant because they may lead to sepsis and even death.

ORAL EVALUATION AND TREATMENT

Fewer problems develop during cancer therapy when oral disease is eliminated, an oral prophylaxis is performed to reduce the bacterial load, and excellent oral hygiene is maintained throughout treatment. The objective of a dental treatment plan is to improve oral function and quality of life. Dental professionals should allow ample time (at least 14 days) prior to cancer therapy for adequate healing. Table 3 includes the important components of a dental treatment plan.⁶ Patients should be provided with written and verbal instructions to ensure they understand the importance of dental issues.

MANAGEMENT OF ORAL IMPLICATIONS

Patients undergoing cancer treatment may experience an increase in dental caries, and this risk may remain elevated for the rest of their lives. Changes in the quality and quantity of saliva, in addition to dietary changes, increase the risk of caries. The saliva becomes more acidic, and cariogenic bacteria may proliferate because of the patient’s inability to clear food from the oral cavity. The patient’s risk of caries is related to the control of bacterial plaque. Excellent oral hygiene and frequent hydration with water, ices, or saliva substitutes will help. Chlorhexidine (0.12%) mouthrinse may be recommended. The nonalcohol version may be less drying and may cause less burning.

Patients must apply 1.1% fluoride gel in a custom tray for 5 minutes to 10 minutes each day during treatment and for the rest of their lives. Patients should also receive a dental prophylaxis and exam every 3 months following completion of cancer treatment. Topical application of fluoride varnish to the tooth surface and exposed cementum should be completed at every appointment.⁶

Mucositis or stomatitis is a direct effect of radiation therapy and cytotoxic chemotherapy. The mucous membrane in the mouth, pharynx, esophagus, and GI tract may become inflamed and ulcerated during treatment. This will increase the risk of pain, oral and systemic infection, and compromised nutrition, which can lead to the development of problems with swallowing and speaking. Mucositis is the primary reason that patients may need a break during chemotherapy, and it is directly related to the neutrophil count at its lowest level (neutropenia). These infections are best treated after cultures determine if the infection is caused by bacteria, viruses, or fungi. During radiation therapy, mucositis usually occurs after the second week and severe symptoms usually resolve within 6 weeks following the completion of cancer therapy.

Bacterial plaque control and consistent hydration can help minimize the severity of mucositis. Recommendations include discontinuing alcohol-based mouthrinses and peroxide mouthrinses, and avoiding foods that are hot, spicy, coarse, and dry, and acidic drinks. Patients should be instructed to consume a diet consisting of soft, bland, sugar-free, and nonirritating foods and beverages. Gentle yet thorough oral care should be performed with an extra soft toothbrush and a bland toothpaste or a paste of baking soda and water.

Patients should continue dental flossing daily unless blood counts become low (platelets less than 50/mm³ to 75,000/mm³and absolute neutrophil count less than 1,000/mm³).⁶ Mouthrinses that soothe the pain of mucositis can be compounded by a pharmacist. Baking soda and water can ease discomfort and neutralize acidity. Patients should rinse the mouth frequently with neutral rinse of ½ teaspoon baking soda and 1 quart water, with or without ½ teaspoon of salt.⁵ None of these strategies will prevent mucositis, but combining preventive therapy strategies can ensure a more successful outcome.
Fungal, viral, and bacterial infections are commonly seen in individuals undergoing cancer treatment. Oral microbiologic culturing and assessment are important to correctly prescribe medications. Candidiasis is common during and following radiation therapy, especially for patients with self-reported xerostomia. There are several antifungal agents effective against candidiasis: topical preparations (Clotrimazole or Nystatin) or systemic medications (Ketoconazole, Fluconazole, or Itraconazole). Chlorhexidine gluconate may prevent candidiasis and assist in reducing candida colonization, but it is not recommended as a primary treatment against clinical infection.⁶

Salivary gland dysfunction may be caused by radiation exposure or indirect exposure from chemotherapy. Radiation therapy causes permanent dysfunction of salivary glands to some degree. Saliva is reduced in quantity and altered in consistency. Reduction is directly related to the total dose of radiation, the degree of gland involvement in the radiation field, and other patient-related variables, such as medication use.

The loss of salivary function leads to multiple adverse consequences, including difficulty tasting, chewing, and swallowing, which results in compromised nutrition; impaired sleep; esophageal dysfunction; intolerance to medications; increased incidence of glossitis, angular chelitiss, candidiasis, and halitosis; increased acidic oral environment, which results in loss of tooth structure and caries; and increased risk of osteoradionecrois.⁶ Patients must be educated about the implications of salivary gland dysfunction. Table 4 provides a list of suggestions for managing xerostomia in this patient population.

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TABLE 4. SUGGESTIONS FOR THE MANAGEMENT OF XEROSTOMIA IN PATIENTS UNDERGOING CANCER TREATMENT.

• Maintain a 3-month maintenance schedule with dental hygienist.
• Brush your teeth after every meal or snack, and rinse mouth thoroughly with water.
• Use topical neutral sodium fluoride in custom fluoride trays daily for 10 minutes.
• Use only sugarfree candies or lozenges to moisturize the mouth.
• Chew gum with xylitol and casein phosphopeptide-amorphous calcium phosphate (Recaldent™) as frequently as possible.
• Drink water (carry it with you at all times) and avoid liquids with carbonation and sugar.
• Use a commercial salivary substitute and oral rinses throughout the day to enhance comfort.
• At bedtime, keep water by the bed and also use an over-the-counter oral moisturizer product.
• Ask the oncologist if systemic treatment may be helpful.

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NECROSIS OF THE BONE

Bone necrosis may occur following high doses of radiation (≥50 Gy) because of the impaired blood supply to the bone. This puts patients at risk of nonhealing infectious wounds, and the threat persists indefinitely.⁶ Factors that may contribute to an increased risk of necrosis include compromised vascularity from previous surgery, poor nutritional or medical status, uncontrolled diabetes, and heavy tobacco or alcohol use. Necrosis may be caused by trauma or it can occur spontaneously. Regardless of cause, necrosis leads to nonhealing soft tissue and bone lesions. Trauma may result from tooth extraction, periodontal procedures, and intraoral prosthetic appliances. The mandible is more susceptible than the maxilla. The nonhealing bone may become infected cause chronic pain, prevent the use of oral prosthesis, and progress into a pathologic fracture.⁶

LEADING THE TEAM

Dental hygienists are well suited to lead the dental team in coordinating care for patients undergoing cancer treatment. While this is most certainly a trying time for these patients, we can improve the ultimate outcomes both in terms of oral health and quality of life.

REFERENCES

1. National Cancer Institute. Cancer Trends Progress Report. Available at: http://progressreport.cancer.gov. Accessed June 3, 2011.
2. Ahmedin J, Siegel R, Jiaquan X, Ward E. Cancer statistics 2010. CA Cancer J Clinic. 2010;60:277–300.
3. Pavlatos J, Gilliam KK. Oral care protocols for patients undergoing cancer therapy. Gen Dent. 2008:56:464–478.
4. Ord RA, Blanchaert RH Jr. Current management of oral cancer. A multi – disciplinary approach. J Am Dent Assoc. 2001;132(Suppl):19S-23S.
5. Barker GJ, Barker BB, Gier RE. Oral Management Of The Cancer Patient: A Guide For The Health Care Professional. 6th ed. Kansas City, Mo: University of Missouri- Kansas City School of Dentistry; 2000.
6. Rankin KV, Jones DL, Redding SW. Oral Health in Cancer Therapy. 3rd ed. Dallas: Texas Cancer Council; 2009.

From Dimensions of Dental Hygiene. June 2011; 9(6): 74-79.