Aggressive treatment for malignant disease may produce unavoidable toxicities to normal cells. The mucosal lining of the gastrointestinal tract, including the oral mucosa, is a prime target for treatment-related toxicity by virtue of its rapid cell turnover rate. The oral cavity is highly susceptible to direct and indirect toxic effects of cancer chemotherapy and ionizing radiation.[1,2] This risk is due to multiple factors including high cellular turnover rates for the lining mucosa, a diverse and complex microflora, and trauma to oral tissues during normal oral function.[3] Although changes in soft tissue structures within the oral cavity presumably reflect the changes that occur throughout the gastrointestinal tract, the following sections focus on oral complications of antineoplastic drugs and radiation therapies.

While oral complications may mimic selected systemic disorders, unique oral toxicities emerge in the context of specific oral anatomic structures and their functions.

Frequencies of oral complications vary by cancer therapy; estimates include the following:

• 10% related to adjunctive chemotherapy.
• 40% related to primary chemotherapy.
• 80% related to hematopoietic stem cell transplantation in which myeloablative conditioning regimens are used (refer to the Assessment of Hematopoietic Stem Cell Transplant Patients section for information on reduced-intensity regimens).
• 100% related to head and neck radiation therapy to fields involving the oral cavity.

The most common oral complications related to cancer therapies are mucositis, infection, salivary gland dysfunction, taste dysfunction, and pain. These complications can lead to secondary complications such as dehydration, dysgeusia, and malnutrition. In myelosuppressed cancer patients, the oral cavity can also be a source of systemic infection. Radiation of the head and neck can irreversibly injure oral mucosa, vasculature, muscle, and bone. This can result in xerostomia, rampant dental caries, trismus, soft tissue necrosis, and osteonecrosis.

Severe oral toxicities can compromise delivery of optimal cancer therapy protocols. For example, dose reduction or treatment schedule modifications may be necessary to allow for resolution of oral lesions. In cases of severe oral morbidity, the patient may no longer be able to continue cancer therapy; treatment is then usually discontinued. These disruptions in dosing due to oral complications can directly affect patient survivorship.

Management of oral complications of cancer therapy includes identification of high-risk populations, patient education, initiation of pretreatment interventions, and timely management of lesions. Assessment of oral status and stabilization of oral disease prior to cancer therapy are critical to overall patient care. This care should be both preventive and therapeutic as indicated to minimize risk for oral and associated systemic complications.

Future research targeted at developing technologies to reduce incidence and severity of oral mucositis, improve infection management, protect salivary gland function, and minimize risk of chronic sequelae is needed. Development of new technologies to prevent cancer therapy-induced complications, especially oral mucositis, could substantially reduce risk for oral pain, oral and systemic infections, and number of days in the hospital; and improve quality of life and reduce health care costs. New technologies could also provide a setting in which novel classes of chemotherapeutic drugs, utilized at increased doses, could lead to enhanced cancer cure rates and durability of disease remission.

References

1. Myers RA, Marx RE: Use of hyperbaric oxygen in postradiation head and neck surgery. NCI Monogr (9): 151-7, 1990.  [PUBMED Abstract]
   
   
2. Schubert MM, Epstein JB, Peterson DE: Oral complications of cancer therapy. In: Yagiela JA, Neidle EA, Dowd FJ: Pharmacology and Therapeutics for Dentistry. 4th ed. St. Louis, Mo: Mosby-Year Book Inc, 1998, pp 644-55. 
   
   
3. Sonis ST, Peterson DE, McGuire DB, eds.: Mucosal injury in cancer patients: new strategies for research and treatment. J Natl Cancer Inst Monogr (29): 1-54, 2001. 
   
   

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