What is nasopharyngeal cancer
Nasopharyngeal cancer is a malignant tumor that affects the upper part of the pharynx, an aerodigestive organ that extends from the back 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 in southern China and Southeast Asia.
Although the cause of nasopharyngeal cancer is not defined for many cases, nasopharyngeal carcinoma is strongly associated with chronic infection by the Epstein-Barr virus (EBV), which is the same virus that causes mononucleosis (the kissing disease). This is the main risk factor for the disease.
The risk of developing nasopharyngeal cancer increases with age, but it can occur in people of all age groups. In the United States, about half of patients with this type of cancer are under 55 years old. In Brazil, approximately 835 new cases are diagnosed annually, which corresponds to 0.14% of all neoplasms.
Subtypes of nasopharyngeal cancer
In most cases, nasopharyngeal cancer is a carcinoma, a tumor that begins in the epithelial cells lining the inner and outer surfaces of the region.
Nasopharyngeal carcinomas are classified by the WHO (World Health Organization) into three subtypes:
- Type 1: Keratinizing squamous cell carcinoma (70-80% related to EBV);
- Type 2: Non-keratinizing differentiated carcinoma (virtually all related to EBV);
- Type 3: Non-keratinizing undifferentiated carcinoma (the most common; virtually all related to EBV).
Nasopharyngeal tumors can also be lymphomas, tumors of the immune system cells found throughout the body, including in the nasopharynx.
Symptoms and signs of nasopharyngeal cancer
The first symptoms of nasopharyngeal cancer often include persistent nasal obstruction, nosebleeds, and the appearance of lumps in the neck – the latter caused by the spread of the disease to the cervical lymph nodes.
Other symptoms include:
- Ear pain and a feeling of fullness in the ears;
- Partial loss of hearing;
- Recurring ear infections;
- Ringing in the ears;
- Persistent sore throat;
- Swelling in the face;
- Nasal discharge;
- Facial paralysis;
- Visual changes.
Diagnosis of nasopharyngeal cancer
The diagnosis of nasopharyngeal cancer should be made by a specialized and experienced physician who suspects the set of symptoms in the patient.
The first examination performed is clinical, with the visualization of the nasopharynx through a special mirror or a flexible tube (endoscope). In the case of the endoscope, it is inserted through the nose or occasionally the mouth so that the doctor can have a good view of the region.
If a tumor is found, a sample of its tissue is removed (biopsy) for analysis by a pathologist, who will confirm or rule out the diagnosis.
After confirmation by anatomopathological examination, imaging tests such as computed tomography, magnetic resonance imaging, and/or PET scan are performed to evaluate the extent of the disease and define the best treatment strategy.
Treatment of nasopharyngeal cancer
Due to its location, surgical treatment of nasopharyngeal cancer is almost always contraindicated. Most patients are treated with a combination of chemotherapy and radiotherapy, and the tumor often responds very well to these treatments.
If the tumor recurs, a new course of radiotherapy, salvage surgery, or systemic treatment with chemotherapy may be considered.
Prevention of nasopharyngeal cancer
There is no screening test that can be done. Reducing exposure to EBV would be the only way to prevent the development of the disease.
