Introduction

Administration of cancer therapy is designed to eliminate or reduce tumor burden. A number of variables, including tumor cell kinetics, site of the tumor, and extent of tissue involvement affect outcome of such treatment. Depending on these and related variables, single or multi-modality therapy may be indicated. Principal forms of therapy include ionizing radiation, surgery, and chemotherapy.

Depending on the extent of the tumor, treatments may not be specific to the tumor; if they are not, normal tissue included within the surgical wound or rapidly replicating normal tissues can be profoundly affected. Injury can be either reversible or irreversible. Because oral epithelium is highly active tissue with replacement times estimated at 9-16 days, chemotherapy and radiation may be directly toxic to the oral mucosa, resulting in dysgeusia, extensive ulceration, pain, bleeding, and (1,2)

compromised normal function. The dental/periapical, periodontal, or salivary gland tissues may suffer acute injury. Radiotherapy can cause both serious destruction to bone and permanent salivary (3-5)

gland disturbances. Because the sequelae associated with cancer therapy may have a profound psychosocial impact on the patient, a multidisciplinary team approach that reviews all aspects of patient care is necessary.

A. State of the Science

Complications of therapy depend on the cancer treatment protocol of choice. Table 1 offers a selected list of oral sequelae associated with therapy.

Surgical Risks and Complications

Surgical management of intraoral lesions typically includes both the primary lesion and the cervical lymph nodes. Ideally, surgery is selected when permanent control of the tumor is likely. Staging of the patient is essential to determine whether surgery alone is indicated or whether radiation or chemotherapy is also needed.

The risks and sequelae of surgery develop directly from and are primarily based on the extent of the tumor and its relationship to contiguous oral structures. Sequelae may include disfigurement and compromise of vascularity and nerve tissue as well as gustatory, masticatory, speech, and swallowing functions
(see Chapter VIII).

Table 1: Selected List of Oral Sequelae Related to Treatment

Ionizing Radiation: Acute Sequelae

salivary gland pathoses

acute parotitis, irreversible hanges (flow rates, compositional alterations)

oral mucositis

Infections

mucosa periodontium

dysgeusia

Ionizing Radiation: Chronic Sequelae

salivary gland pathoses

acute parotitis

irreversible changes (flow rates, compositional alterations) dental alterations

rampant caries

demineralization osteoradionecrosis dysgeusia trismus

laryngeal alterations

Surgery: Chronic Sequelae

cosmetic alterations functional disturbances

speaking

mastication

swallowing vascular compromise nerve damage muscular atrophy

Chemotherapy

oral mucositis dysgeusia

immune dysfunction

dentition

infections

mucosa

periodontium

hemorrhage

salivary dysfunction (variable)

Surgery: Acute Sequelae

functional disturbances speaking mastication swallowing vascular compromise

 

Risks and Sequelae of Radiation or Chemotherapy

Mucositis and Infection

Mucositis can be caused by either radiation or chemotherapy; the severity and extent of lesions are correlated with the treatment protocol being administered. Radiation-induced mucositis depends on absorbed radiation dose, fractionation, delivery modality, and soft tissue status. The patient may feel a mucosal “burning” sensation 1-2 weeks after initiation of therapy; the mucosa may be edematous and leukoplakic or erythematous on clinical examination. Depending on the intensity of the therapy and patient variables, extensive ulcerations may develop following initial clinical signs and symptoms. With chemotherapy, outcomes are specifically related to the pharmacologic class of drug selected as well as its dose concentration and the extent of neutrophil depletion or leukopenia.

Strategies for preventing mucositis are limited, but the problem can be partially minimized by fractionation techniques, shielding, and modifying modes of delivery. Supportive care for the acute components of mucositis (bleeding, pain, and infection) is the mainstay of treatment. Although not directed principally at preventing mucositis, comprehensive oral care, including mechanical plaque removal supplemented by an antimicrobial rinse if indicated and frequent rinsing with saline bicarbonate solutions, can reduce the severity of secondary complications. Topical anesthetics or systemic analgesics are administered frequently for palliation of pain. Smoking can exacerbate mucositis; patients should be assisted with cessation using nicotine replacement therapy if indicated. (6)

Candidiasis is the most common oral infection during treatment for oral cancer, although other mycotic, bacterial, or viral infections are possible. Prophylactic or therapeutic topical and/or systemic antifungal agents are necessary to control candidiasis. Selection of an antifungal agent must consider the patient’s degree of xerostomia and possible inability to dissolve a troche. Also of concern is the patient’s level of oral hygiene and the risk associated with high levels of sucrose in topical preparations. The addition of chemotherapy to the treatment protocol may increase the severity of mucositis, xerostomia, and infection; it also increases the risk of bacterial and herpetic infections.

Because of the high probability of mucositis and infection, their potential severity, and their nutritional consequences, the radiation or chemotherapy patient needs comprehensive management protocols, particularly during periods of highest infection risk. Some cancer centers prescribe a “cocktail” preparation of antimicrobials, a steroid, a coating agent, and a topical anesthetic. However, the effectiveness of such preparations is empirically based and needs to be examined in a well-controlled clinical study.

Salivary Gland Dysfunction

Directing radiation therapy to the salivary glands or administering chemotherapeutic, antiemetic, or psychotropic drugs may alter salivary gland function. Chemotherapy does not typically cause chronic salivary gland changes; in contrast, high-dose ionizing radiation delivered to major glandular sites can cause permanent salivary gland dysfunction. The degree of oral dryness (xerostomia) will vary by the extent of salivary gland injury. These changes can exacerbate oral infection risk at various sites, including the mucosa and perio