______________________________________________ Oral Cancer and Complications of Cancer Therapies
and vertebrae. The agranular leukocytes are produced both in the red bone marrow and lymphoid tissue, such as the tonsils, spleen, and lymph nodes. Erythrocytes, containing their large hemoglobin molecules, are essential for carrying oxygen to the tissue. Platelets are a critical component of the blood clotting mechanism. The granular and agranular leukocytes serve dif- ferent functions within the immune system. Any procedure or medication that interferes with the production of any of these components can cause systemic problems. Chemotherapy is a significant source of these problems. HEMORRHAGE When the number of platelets produced or the quality of those in existence are diminished, oral bleeding can occur. The normal range of platelets is 150,000–450,000 per mm 3 of blood. Spontaneous bleeding occurs when the platelet count decreases to 20,000–50,000 per mm 3 of blood [78]. When platelets contact a damaged blood vessel, they increase in size and adhesiveness and form a plug upon the damaged vessel. Some chemotherapeutic agents alter the ability of platelets to adhere to each other in the formation of a fibrous plug, which is required for hemostasis. Others may interfere with actual platelet production and decrease the number of platelets avail- able. Regimens that use more than one chemotherapeutic agent may affect both platelet quality and production. Interference with coagulation causes oral manifestations, including petechiae, ecchymoses, or oozing of blood [79]. The most common areas in which petechiae are found intraorally include the palate, gingiva, lips, and tongue. Petechiae are small areas of bleeding within the tissue that occur because of a decreased platelet count. Similarly, bleeding submucosally or subcutaneously due to platelet deficiencies in quality or quantity may produce ecchymoses. These lesions can occur anywhere within the oral tissues and appear as a dark red or reddish-blue area submucosally. They are exacerbated by acci- dental trauma or by prostheses that irritate the tissues. The most disconcerting problem for the patient is hemorrhage, which occurs spontaneously or with actions such as eating, brushing, or flossing. This problem is exacerbated in patients who have chronically inflamed gingival tissues characteristic of gingivitis and periodontal disease. Ideal depth of the gingival sulcus in health is 3 mm or less. As gingivitis and periodon- tal disease progress, destruction of the epithelial attachment causes this sulcus to become deeper. Cleansing the pocket depth becomes increasingly difficult, with a resultant state of chronic inflammation. As alveolar bone is lost during the progression of periodontal disease, the gingival tissues become poorly attached to the tooth and bone. An environment of continually deepening periodontal pockets causes severe soft tissue inflammation. Despite this, tissues in this pathologic state often do not bleed spontaneously. Patients receiving chemotherapy, however, may have spontaneous gin- gival bleeding even if the depth of the gingival sulcus is not excessive. The clots usually appear as dark red and are friable, with slight bleeding evident when they are removed. Patients
may experience this at any time, but it is most noticeable upon awakening in the morning. Dried blood from nocturnal bleeding can be encrusted on the lips, tongue, or anywhere in the oral mucosa. Sharp edges of fractured teeth or broken fillings, dental restorations that extend below the gingival crest, prostheses that cause tissue irritation, and partially erupted wisdom teeth are all potential sources that compromise tissue integrity and allow easy bleeding during chemotherapy. When bleeding is seen within the oral cavity, the patient should be referred to their physician, as internal bleeding in other areas of the body is possible. The effect of chemotherapy on hemostasis subsides for most patients after the completion of the regimen. Even basic dental treatment, including prophylaxis, should not be performed until laboratory values ascertain that the platelet levels have returned to a range that is acceptable for hemostasis. Further diagnostic tests, such as a prothrombin time, may need to be done. The oncologist should be consulted before any invasive treatment is planned, as patients can have a wide interval of recovery times after chemotherapy ends. Emergency dental treatment that cannot be postponed, such as oral and maxil- lofacial trauma or painful exacerbations of dental problems, may need to be performed in a hospital setting. INFECTIONS Oral infections that are usually treated successfully with standard antibiotics can become a life-threatening problem for patients receiving chemotherapy. Oral infections may be bacterial, fungal, or viral in origin. Chemotherapy interferes with the production of the granular and agranular leukocytes, which are important components of the defense mechanism of the immune system. Oral infections in the aftermath of chemotherapy are common and may manifest into systemic conditions [80]. Bacterial Infections As mentioned, the normal host defense mechanisms and competitive inhibition among the oral microflora organisms are altered in many patients after chemotherapy. Any bacte- rial species have the potential to become a local or systemic pathogen. Pathologic dental conditions that preclude adequate cleansing, such as periodontal disease, necrotic pulps that have caused periapical infections, or partially erupted wisdom teeth, are potential sources of acute infections in patients receiving chemotherapy. The denuded, ulcerated areas of mucositis also facilitate a means of systemic bacterial dissemination. Antibacterials are indicated either as prophylaxis or as treat- ment if patients present with clinical signs of infection [81]. Fungal Infections Oral infections of fungal origin (with the potential to spread systemically) occur in as many as 38% of patients receiving chemotherapy [80]. As mentioned, C. albicans is a resident fungal organism in the oral microflora. This opportunistic pathogen thrives in the oral environment of a host who is
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