Familial Nasopharyngeal Carcinoma 6

Long-Term Complication in the Treatment of Nasopharyngeal Carcinoma 277Fig. 22.1. Radiation-induced xerostomia. (Courtesy of MichaelKahn, DDS)reduction of taste acuity, dysphagia, poor denture fitting,and dysfunction of phonation are also associated,at least in part, with xerostomia (Figs. 22.1 and 22.2).NPC is a highly curative malignancy, especially inits early stages by radiation therapy and the majorityof NPC patients become long-term cancer survivors.The occurrence of moderate to severe xerostomia isnearly universal after convention radiation therapyfor NPC (Lee et al. 1992, 2009). As in any other typesof squamous cell carcinoma (SCC) of the head and necktreated by radiation therapy, the chronic adverseeffectssecondary to radiotherapy affect patients’ qualityof-life(Spielman 1990; Harrison et al. 1997; Epsteinet al. 1999).With significant xerostomia and other complicationssuch as mucositis, substantial loss of appetitewill lead to reduction in dietary intake. Treatmentinducedweight loss in NPC certainly affects patients’quality of life during treatment. In addition, substantialweight loss may cause body contour change thatis significant enough to alter the radiation dose distribution,thus adversely affecting the treatment outcome(Wang et al. 2009).The diagnosis of radiation-induced xerostomia isusually subjective, and the assessment of severity of thesymptoms can be achieved by using self-report instrumentsand visual analog scales. Objective assessmentof the severity of xerostomia utilizes parameters suchas stimulated and unstimulated salivary flow rates. Thescoring criteria for both acute and late salivary glandtoxicity advocated by the Radiation Therapy OncologyGroup and the European Organization for Researchand Treatment of Cancer (RTOG/EORTC) largelydepend on subjective measure of xerostomia(Table 22.1 and 22.2) (Cox et al. 1995). The CommonTerminology Criteria for Adverse Events v3.0 (CTCAEv3.0) that are used for both acute and late effects ofTable 22.1. RTOG scoring for acute radiation-induced salivarygland morbidity (Nicolatou-Galitis et al. 2003)GradeCriteria0 No change over baseline1 Mid dryness, slightly thickened saliva, andslightly altered or metallic taste2 Moderate to complete dryness, thick stickysaliva, and markedly altered tasteFig. 22.2. Dental caries secondary to radiation therapy.(Courtesy of Michael Kahn, DDS) (Permission to use picturegranted by Dr. Michael Kahn, DDS)3 Not defined for acute xerostomia4 Acute salivary gland necrosis