Pretreatment assessment and dental management of patients with nasopharyngeal carcinoma
Introduction
It is well recognized that oral/dental assessment is essential for patients who will receive radiation therapy to the head and neck1, 2, 3, 4, 5, 6, 7, 8. This was demonstrated in a study of 250 consecutive patients examined prior to radiation therapy, where 68% were identified as requiring immediate dental treatment, and even in edentulous patients, 21% required treatment for ill-fitting dentures[1]. Furthermore, only 11% of patients receiving regular dental treatment were considered dentally fit and, therefore, the majority needed dental treatment prior to radiation therapy[1]. Treatment should include removal of teeth that are to be included in the high dose of planned irradiation that cannot be maintained for a lifetime. Removal of rough dental surfaces (broken teeth, irregular restorations and prostheses, calculus), stabilization of dental decay particularly if threatening the pulp, and oral hygiene instruction is needed. When xerostomia is predicted, a preventive caries prevention program should be instituted. Teeth that should be extracted include non-restorable teeth and teeth with advanced periodontal disease with adequate time for healing prior to beginning radiation therapy. Long-term maintenance is part of this therapy.
Long-term complications of radiation therapy include potential effects on growth and development, compromised vasculature due to endarteritis, and effect upon salivary gland function. The results of xerostomia include continuing risk for oral candidiasis, rampant caries, difficulty with dentures, and effects upon speech and taste. Long-term complications were assessed in 20 patients (mean age 6 years) with head and neck soft tissue sarcomas evaluated following treatment that included radiation therapy and chemotherapy[9]. The major problems identified in these patients were dry eyes and cataracts, hearing loss, effects on eruption of teeth and caries, dry mouth and craniofacial deformity. It was concluded that multi-disciplinary follow-up is needed for children following radiation therapy[9]. A study of 73 head and neck cancer patients found that the incidence of dental extractions decreased following radiation therapy in those using fluoride; however, no differences were seen between fluoride gel or fluoride rinse application[4]. While extractions were decreased, an increased number of restorations were placed, suggesting that compliance with preventive measures is associated with more regular dental visits[4]. We have assessed patients following head and neck radiation therapy to determine the impact of xerostomia upon caries risk and the effect of fluoride gel application on caries risk[10]. We found that regular reinforcement of fluoride application is needed following radiation therapy in order to maintain patients’ compliance[10].
Nasopharyngeal cancer (NPC) is a relatively rare neoplasm in the United States[11]. Data from the Surveillance Epidemiology and End Results (SEER) program in the United States (1973–86) show 1645 cases, with the highest rates in ethnic Chinese, followed by Filipinos, blacks and whites[12]. No changes were evident in incidence during the study period[12]. We have previously reported the head and neck symptoms that are associated with NPC[13]. Head and neck pain was an important identifying symptom of NPC. Symptoms prior to diagnosis included headaches, neck masses, ear complaints (hearing changes, dizziness, plugged sensations, pain), nose bleeds and stuffiness, reduced or altered smell, jaw pain, limited jaw opening, facial pain or numbness, and neck masses[13]. These symptoms can be nonspecific and present diagnostic challenges, and may present with overlapping symptoms of temporomandibular disorders[13]. Unfortunately, NPC is often not diagnosed until advanced.
The risk of developing NPC is 30 times greater in Chinese people than in any other ethnic group. The risk is highest among people of southeast Asian ancestry, particularly residents of Kwantung province in south China, with men at double the risk for women14, 15. Predisposing factors to this type of cancer include genetic predisposition, increased size of the nasopharynx in the south Chinese, smoking, working in poor ventilation, use of nasal balms or oils, herbal drugs, ingestion of salted fish, and high Epstein–Barr virus (EBV) antibody titre (specifically anti-IgA VCA)16, 17, 18, 19, 20, 21, 22.
We undertook this study of patients evaluated prior to treatment for NPC, because there are no reports in the literature that have studied the need for dental treatment in a cohort of patients with NPC prior to radiation therapy. This study also provided an opportunity to assess reported risk factors for NPC in a North American population.
Section snippets
Methods
The records of the British Columbia Cancer Agency were reviewed for all patients diagnosed with NPC between November 1988 and July 1992. All patients were treated with primary radiotherapy. The dose to the nasopharynx was 6250 cGy, delivered over 30 treatments in daily fractions of 200 to 225 cGy. The customary field setup employed leads to high-dose bilateral exposure of the molar teeth in the maxilla and mandible, and all the major salivary glands. The patient’s history of potential risk
Results
Fifty-seven patients were seen in a 45 month period (Table 1). The mean age was 49.7 years (+13.2 years; range 20–83 years). There were 41 males, and 16 females. The ethnic origin was Asian (44), Caucasian (11), Northwest native Indian (1), and Indo-Pakistani (1). The majority of the Asian patients originated from Hong Kong or China (33). The tumor type and TNM descriptions are shown in Table 1. The majority of patients were diagnosed with advanced stages of disease (Table 2). Treatment of this
Discussion
The mean age of the patients (49.7±13.2 years) in this study was similar to that of other studies[23]. The majority of patients were of Asian origin (78%). We have previously reviewed the symptoms associated with the recognition of NPC[13], and noted that head and neck pain may overlap with temporomandibular disorders, and other causes of facial pain. The overlap in symptoms, and the difficulty in thorough examination of the nasopharynx present challenges in diagnosis. Unfortunately, diagnosis
Acknowledgements
The authors acknowledge the contribution of Jack Zolty in data entry.
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