Pretreatment assessment and dental management of patients with nasopharyngeal carcinoma

Abstract

Patients who present with nasopharyngeal carcinoma (NPC) require thorough oral and dental assessment prior to treatment of the malignancy. We assessed the oral status of 57 consecutive patients with a diagnosis of NPC. In this study, identified risk factors for NPC were seen to be different in Asian versus non-Asian patients. Epstein–Barr virus seropositivity was seen in all Asian patients and in 69% of non-Asian patients (P=0.00006), and reported alcohol use was greater in the non-Asian patients. In this study it was found that 68% of dentate patients required dental extractions primarily due to periodontal disease. Even in patients who reported receiving regular dental care (28%) extractions prior to radiation therapy were suggested. Oral complications of radiation therapy were reported by 84% of patients, with the most common being xerostomia. Clinical diagnosis of candidiasis (16%), rampant caries (10% of dentate patients) and difficulties with dentures (25% of denture wearers) were noted. In addition to pretreatment assessment, continuing oral and dental management is needed for patients with NPC.

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.