What is nasopharyngeal cancer
Nasopharyngeal cancer is a malignant tumor that affects the upper portion of the pharynx, an aerodigestive organ that extends from the bottom of the nose to the larynx and esophagus. It is a rare type of head and neck cancer, with an incidence of less than one case per 100,000 people per year in most parts of the world. In some regions, however, this incidence is higher, such as southern China and Southeast Asia.
Although the cause of nasopharyngeal cancer is unknown for many cases, nasopharyngeal carcinoma is strongly related to chronic infection with the Epstein-Barr virus (EBV), which is the same virus that causes mononucleosis (kissing disease). This is the main risk factor for the disease.
The risk of developing nasopharyngeal cancer increases with age, but it can affect people from all age groups. In the US, about half of patients with this type of cancer are under 55 years old. In Brazil, about 835 new cases are diagnosed annually, which corresponds to 0.14% of all neoplasms.
Types of nasopharyngeal cancer
In most cases, nasopharyngeal cancer is a carcinoma, a tumor that starts in the epithelial cells that line the internal and external surfaces of the area.
Nasopharyngeal carcinomas are classified according to the WHO (World Health Organization) into the following three categories:
- Type 1: keratinized squamous cell carcinoma (70-80% EBV-related);
- Type 2: differentiated non-keratinized carcinoma (nearly all EBV-related);
- Type 3: undifferentiated non-keratinized carcinoma (most common; virtually all EBV-related).
Nasopharyngeal cancer can also be a lymphoma, a tumor of immune cells found throughout the body, including the nasopharynx.
Symptoms and signs of nasopharyngeal cancer
The first symptoms of nasopharyngeal cancer are often persistent nasal obstruction, nosebleeds and lumps in the neck – the latter caused by the disease spreading to the cervical lymph nodes.
Other symptoms include:
- Pain and clogged feeling in the ears;
- Partial hearing loss;
- Repeated ear infection;
- Ringing in the ears;
- Persistent sore throat;
- Swelling in the face;
- Secretion through the nose;
- Facial paralysis;
- Visual changes.
Diagnosis of nasopharyngeal cancer
The diagnosis of nasopharyngeal cancer must be made by a specialized and experienced physician who is suspicious of the patient’s set of symptoms.
The first exam performed is clinical, with the visualization of the nasopharynx through a special mirror or a flexible tube (endoscope). In the case of the endoscope, a device is placed through the nose or the mouth to give the doctor a good view of the area.
If a tumor is found, a sample of its tissue is taken (biopsy) for analysis by a pathologist, who will confirm the diagnosis.
After anatomopathological confirmation, imaging tests such as computed tomography, magnetic resonance and/or PET Scan are performed to assess the extent of the disease and define the best treatment strategy.
Due to its location, surgical treatment of nasopharyngeal cancer is almost always not recommended. Most patients are treated with a combination of chemotherapy and radiation, and the tumor usually responds very well to these treatments.
If the tumor is recurrent, further radiation therapy, surgical salvage, or systemic chemotherapy by itself may be considered.
There is no recommended screening test. Reducing exposure to EBV would be the only way to prevent the development of the disease.