Oral Cancer and Complications of Cancer Therapies _ _____________________________________________
Management of less severe grades of mucositis consist of pal- liative relief of pain, the monitoring and treatment of localized infections that may develop, and monitoring the patient’s abil- ity to maintain an oral care regimen and an adequate nutrition level. Liquid forms of systemic analgesics and antibiotics may be easier for the patient to swallow. Topical liquid anesthetics such as 2% viscous lidocaine may provide temporary analgesia. Because these patients may be taking medications for other conditions, care should be taken to avoid any adverse drug interactions. Prednisone, 40 mg to 80 mg per day prescribed for one week or less, may help to resolve some of the inflammation [47]. Varied rinses of sodium chloride and sodium bicarbonate may allow for tissue cleansing, moistening, and lubricating and are well tolerated. These rinses, along with proper oral hygiene and hydration, are mainstays of prevention and treatment. Chlorhexidine 0.12% rinses are useful but have a tendency to cause discomfort and nausea. Evidence supporting their use is generally inadequate and/or conflicting [48]. There is increasing evidence that severe oral mucositis due to radiotherapy may be pre-empted with palifermin, a recombi- nant human keratinocyte growth factor, though this use is an off-label use [49]. Palifermin is approved by the U.S. Food and Drug Administration for the treatment of severe oral mucositis in patients with hematologic malignancies undergoing total body irradiation, stem-cell transplantation, and chemotherapy [50]. Though the agent is expensive, oral mucositis is often reported to be the most torturous side effect of cancer treat- ment and may necessitate the cessation of radiotherapy even with advanced-stage malignancies. Evidence supporting the use of palifermin is conflicting [48]. The prophylactic palifermin regimen begins with one 60 mcg/kg IV dose three days prior to treatment and three days following treatment up to a maximum of six doses [51]. The most common side effect is skin rash/erythema [51; 52]. A 2011 study examined its use in patients with head and neck cancer undergoing postoperative radiochemotherapy and found a modest reduction in the incidence of severe mucositis in those given palifermin (51%) versus placebo (67%), but the primary outcome was the reduction in duration of severe mucositis (4.5 days versus 22 days, respectively) [53]. A phase 3 clinical trial to determine safety and efficacy as an adjuvant treatment for those with head and neck cancers undergoing radiochemotherapy was completed in 2016, but the results of the study have not been published [54]. Palifermin use should be carefully considered for patients at increased risk of developing severe mucositis [51; 52]. Pediatric patients and the elderly are at an increased risk; other risk fac- tors include existing periodontal disease, poor diet, alcohol use, tobacco use, certain medications, oxygen therapy, and changes in breathing [55].
The Oral Assessment Guide (OAG), developed by Eilers, may be used in the staging of mucositis and when creating a management plan ( Table 5 ) [56]. Using the OAG, the patient is assigned a number of points, from 1 to 3, in each of eight categories, with a total score of 8 indicating no change and a total score of 24 indicating severe mucositis. The OAG has been shown to be effective and reasonably easy to use in sev- eral studies [57; 58]. It provides for objective assessment (as it omits pain as a measure of severity) and is able to identify subtle changes in status when used daily, thus ensuring rapid intervention. Another assessment tool is the World Health Organization scale, which despite its simplicity, is regarded as the most effective instrument used worldwide (followed by the OAG) [56; 58]. Whichever tool is implemented, daily evalua- tion using a standardized assessment instrument is considered to be an integral part of oral mucositis management and should also be used at every patient contact [55; 56; 57; 58]. Self-assessment using the OAG can also be taught for closer observations. While mucositis usually resolves after radiotherapy is com- pleted, other radiotherapy-induced problems may be long-term or permanent. These include changes in the salivary glands, caries due to radiation, and osteoradionecrosis. SALIVARY GLAND CHANGES Saliva has several critical functions in the oral environment. Its chemical composition allows it to function as a lubricant, a buffer in the modulation of acidity (pH) levels, an initia- tor in the enzymatic process of digestion, and as part of the immune system. The immune function is not readily apparent but is critical in maintaining the delicate balance of the oral microflora. Certain salivary proteins inhibit microbial growth. Lysozyme, a salivary enzyme, can hydrolyze and thus destroy certain components of the bacterial cell wall. Immunoglobulin (Ig) is also secreted into saliva, with IgA being the predominant secretion. Small amounts of IgG and IgM are also secreted. These substances may exert their action by decreasing bacte- rial adherence to hard and soft tissue. The pH of saliva ranges from 6.7 (a weak acid) to 7.4 (a weak base) [59]. Alteration of this range toward either spectrum promotes certain forms of microbial growth over others. Lactobacillus and Streptococcus mutans , two cariogenic resident bacterial species, favor a more acidic environment. This situation occurs when salivary output decreases secondary to radiation therapy [60]. The parotid, submandibular, and sublingual glands com- promise the major salivary glands. Scattered throughout the remainder of the oral mucosa are minor salivary glands. Location of the radiation portal will determine which gland or glands will be susceptible to damage. Because the secretory product of each gland varies, postradiation salivary composi- tion will be determined by which gland or glands are damaged and which are spared.
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