Definition
Nasopharyngeal carcinoma (NPC) is a tumor arising from the epithelial cells that cover the surface and line the nasopharynx. NPC was first described as a separate entity by Regaud and Schmincke in 1921. Approximately one third of nasopharyngeal carcinomas of the undifferentiated type are diagnosed in adolescents or young adults. Although rare, NPC accounts for one third of childhood nasopharyngeal neoplasms (data from USA).
Description
a malignant neoplastic disease of the nasopharynx. Depending on the site of a nasopharyngeal tumor, there may be nasal obstruction, otitis media, hearing loss, sensory or motor nerve damage, bony destruction of the skull, or deep cervical lymphadenopathy. Diagnostic measures include nasopharyngoscopy, biopsy, and radiologic examination of the skull with tomographic studies. Squamous cell and undifferentiated carcinomas are the most common lesions. Nasopharyngeal cancer occurs rarely in the United States and frequently in southern China. Exposure to dusts of nickel, chromium, wood, and leather and to isopropyl oil increases the risk of developing nasopharyngeal cancer. High titers of antibodies to the Epstein-Barr virus are found in Chinese patients with the cancer, and there is evidence of genetic susceptibility, because a certain histocompatibility antigen is associated with the disease and multiple cases occur in some families. Radiation is the most effective therapy, and chemotherapy is also used.
Nasopharyngeal carcinoma (NPC) is a tumor arising from the epithelial cells that cover the surface and line the nasopharynx. The annual incidence of NPC in the UK is 0.3 per million at age 0–14 years, and 1 to 2 per million at age 15–19 years. Incidence is higher in the Chinese and Tunisian populations. Although rare, NPC accounts for about one third of childhood nasopharyngeal neoplasms. Three subtypes of NPC are recognized in the World Health Organization (WHO) classification:
- squamous cell carcinoma, typically found in the older adult population
- non-keratinizing carcinoma
- undifferentiated carcinoma
The tumor can extend within or out of the nasopharynx to the other lateral wall and/or posterosuperiorly to the base of the skull or the palate, nasal cavity or oropharynx. It then typically metastases to cervical lymph nodes. Cervical lymphadenopathy is the initial presentation in many patients, and the diagnosis of NPC is often made by lymph node biopsy. Symptoms related to the primary tumor include trismus, pain, otitis media, nasal regurgitation due to paresis of the soft palate, hearing loss and cranial nerve palsies. Larger growths may produce nasal obstruction or bleeding and a "nasal twang". Etiological factors include Epstein-Barr virus (EBV), genetic susceptibility and consumption of food with possible carcinogens – volatile nitrosamines. The recommended treatment schedule consists of three courses of neoadjuvant chemotherapy, irradiation, and adjuvant interferon (IFN)-beta therapy.