(See also Overview of Head and Neck Tumors.)
Nasopharyngeal cancer can occur in any age group, including adolescents, and is common in the South China Sea region. Although rare in the US and Western Europe, it is common in Asia and is one of the most common cancers among Chinese immigrants in the US, especially those of southern Chinese and Southeast Asian ancestry. Over several generations, the prevalence among Chinese-Americans gradually decreases to that among non-Chinese Americans, suggesting an environmental component to etiology. Dietary exposure to nitrites and salted fish also is thought to increase risk. Epstein-Barr virus is a significant risk factor, and there is hereditary predisposition.
Other nasopharyngeal cancers include adenoid cystic and mucoepidermoid carcinomas, malignant mixed tumors, adenocarcinomas, lymphomas, fibrosarcomas, osteosarcomas, chondrosarcomas, and melanomas.
Nasopharyngeal cancer often presents with palpable lymph node metastases in the neck. Another common presenting symptom is hearing loss, usually caused by nasal or eustachian tube obstruction leading to a middle ear effusion. Other symptoms include ear pain, purulent bloody rhinorrhea, frank epistaxis, cranial nerve palsies, and cervical lymphadenopathy. Cranial nerve palsies most often involve the 6th, 4th, and 3rd cranial nerves due to their location in the cavernous sinus, in close proximity to the foramen lacerum, which is the most common route of intracranial spread for these tumors. Because lymphatics of the nasopharynx communicate across the midline, bilateral metastases are common.
Patients suspected of having nasopharyngeal cancer must undergo examination with a nasopharyngeal mirror or endoscope, and lesions are biopsied. Open cervical node biopsy should not be done as the initial procedure (see Neck Mass), although a needle biopsy is acceptable and often recommended.
Gadolinium-enhanced MRI (with fat suppression) of the head with attention to the nasopharynx and skull base is done; the skull base is involved in about 25% of patients. CT also is required to accurately assess skull base bony changes, which are less visible on MRI. A PET scan also commonly is done to assess the extent of disease as well as the cervical lymphatics. (See table Staging of Nasopharyngeal Cancer.)
Staging of Nasopharyngeal Cancer
Patients with early-stage nasopharyngeal cancer (see table Staging of Nasopharyngeal Cancer) typically have a good outcome (5-year survival is 60 to 75%), whereas patients with stage IV disease have a poor outcome (5-year survival is < 40%).
Because of the location and extent of involvement, nasopharyngeal cancers often are not amenable to surgical resection. They are typically treated with chemotherapy and radiation therapy, which are often followed by adjuvant chemotherapy.
Recurrent tumors can be treated with another course of radiation, commonly with brachytherapy (radioactive implant placement); radionecrosis of the skull base is a risk. An alternative to radiation, for highly selected patients, is skull base resection. Resection is usually done by removing part of the maxilla for access but, in select cases, resection can be done endoscopically, although little data yet exists on endoscopic resection. (See also the National Cancer Institute’s summary Nasopharyngeal Cancer Treatment.)
Palpable lymph nodes in the neck are the most common presenting finding in nasopharyngeal cancer; other symptoms include nasal congestion with epistaxis, blood in the saliva, and hearing loss.
Diagnose nasopharyngeal cancer with nasal endoscopy and needle biopsy and use CT, MRI, and PET scanning for staging.
Treat nasopharyngeal cancer with chemotherapy plus radiation therapy and sometimes surgery.