Oral Cancer and Complications of Cancer Therapies _ _____________________________________________
should demonstrate that proper flossing technique is within their capability. Mouth rinses that contain alcohol may irritate the mucosal tissues and increase the dryness within the mouth. If an alco- hol-based mouth rinse can be tolerated, 0.12% chlorhexidine gluconate is an excellent adjunct to the oral hygiene regimen [73]. This mouth rinse has substantivity, the ability to adhere to the tissues within the oral environment for several hours. This bactericidal formulation diminishes the number of bac- teria associated with dental caries and periodontal disease. However, as discussed, chlorhexidine may cause additional discomfort for many patients [48]. All patients who will retain some or all of their natural teeth should have custom fluoride trays made before oral cancer treatment. These trays serve as reservoirs for a neutral formu- lation of 1.1% sodium fluoride or 0.4% stannous fluoride gels, depending on the composition of the patient’s dental restorations [74]. These trays should be worn about 10 minutes daily, and patients should refrain from eating or drinking for 30 minutes after the fluoride treatment. Patients who do not want to use trays may brush the gels onto their teeth. Patients should brush their teeth after eating using a soft toothbrush and fluoride toothpaste [75]. This regimen should be a lifelong commitment for these patients in an attempt to minimize the risk of dental caries in a postsurgical oral environment that poses a high risk of dental caries. POST-TREATMENT CONSIDERATIONS Before surgery and radiotherapy for oral cancer is begun, patients should have an appointment for an oral assessment. The status of the teeth and the soft tissue should be scrutinized to minimize the chance of any condition that would lead to an infection necessitating oral surgery procedures, especially after radiotherapy. If a dental emergency develops that requires an extraction of a tooth, a 14-to 21-day window of healing should be allowed prior to radiotherapy to minimize the risk of ORN. Recall appointments should be frequent to allow for the examination of the oral tissues, as there is always a chance that an oral malignancy can recur at the original site or a new lesion can arise. These appointments also allow for an opportunity to evaluate oral hygiene status, presence of carious lesions, periodontal condition, and overall condition of the oral mucosa. Rehabilitation of the patient with oral cancer is a challenging experience. The extent of necessary rehabilitation is propor- tionate to lesion size and the presence of metastasis. Larger squamous cell carcinoma lesions can engulf nerves, muscle, and bone. As noted, the removal of larger lesions adversely affects the ability to eat, speak, swallow, and enjoy the previous quality of life. Cosmetic disfigurement may not always be correctable to the patient’s satisfaction. The team approach, involving the surgical and radiotherapy team, dentists, oral surgeons, oral and maxillofacial prosthodontists, nurses, nutritionists, occupational therapists, speech therapists, physical therapists,
pharmacists, and plastic surgeons, may be needed. Counseling may be necessary to assist these patients as they face life from an entirely new perspective. Because most patients with oral cancer have a history of tobacco use, tobacco cessation educa- tion is an important aspect of patient recovery.
ORAL COMPLICATIONS FROM CHEMOTHERAPY
According to the Centers for Disease Control and Prevention, the death rate caused by cancers of all types is second only to heart disease [76]. During the 1990s, the incidence of cancer and death rates from this group of diseases actually declined. However, due to an increasing population, the actual number of deaths from cancer has increased [76]. Malignancies that involve individual organs, organ systems, or the bone marrow are usually treated by surgery, chemotherapy, and localized radiotherapy. When the primary lesion of squa- mous cell carcinoma arises within the oral cavity, chemother- apy is not typically a part of treatment. When chemotherapy is used postsurgically for organic or systemic malignancies, severe oral complications may also occur. When radiotherapy involves treatment of a malignant neoplasm that is distant from the oral and maxillofacial complex, oral complications rarely develop. Because chemotherapy regimens are introduced intravenously, these drugs can interact with cells anywhere in the body. Chemotherapeutic agents exert their effects by interaction with the nuclei of malignant cells. Interference with DNA production, separation of the DNA helix, and disruption of protein synthesis are mechanisms by which the rapidly dividing and highly mitotic malignant cells are destroyed [77]. Normal cells, which undergo frequent turnover, can only be replaced if their successors also undergo frequent mitosis and cell divi- sion. Many chemotherapeutic agents exert their deleterious effect on normal cells as a result of the mitotic similarities between rapidly dividing malignant cells and those of normal cells. Because the cells of the oral mucosa undergo frequent turnover, they are subject to the nonspecific detrimental effects of chemotherapy. The oral tissues are also subject to other problems, such as bleeding and infection, caused by the effects of chemotherapy on the cells from which the formed elements of human blood are produced. A review of these cells and their functions in the clotting mechanism and in appropriate immune function is necessary before the effects that chemotherapy has on these cellular elements, and ultimately the host, can be understood. All blood cells are formed through the process of hematopoie- sis, beginning with an undifferentiated cell, the hemocytoblast. Erythrocytes, platelets (thrombocytes), and the spectrum of the granular leukocytes (neutrophils, basophils, and eosinophils) are produced in the red bone marrow. This productive tissue is located in several bones, including the sternum, ribs, pelvis,
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