The nasopharynx is the top part of the pharynx. It sits behind the nose and nasal cavity, right below the base of the skull. It lies above the soft part (soft palate) of the roof of the mouth. The nostrils lead to the nasopharynx, which helps to pass air through the pharynx. The nasopharynx also has an opening on each side that leads to the ears.
The pharynx has three parts: the nasopharynx (upper part), the oropharynx (the middle part) and the hypopharynx (the lower part). It carries air to the trachea (windpipe) and food to the esophagus (from the throat to the stomach).
Several types of tumors, both cancerous and not cancerous, can develop in the nasopharynx. They can begin from a variety of different cell-types found in the nasopharynx. Benign tumors (not cancer) occur in rare cases in children and young adults. They may form in the vascular (blood-carrying) system or the minor salivary glands of the nasopharynx. Sometimes treatment is not needed. On the other hand, when tumors are found to be cancerous, treatment is critical.
Malignant Nasopharyngeal Tumors
Nasopharyngeal carcinoma (NPC) is a very rare cancer found in the nasopharynx. NPC mainly begins in epithelial cells, which are found throughout the body, and line the nasopharynx. There are three types of nasopharyngeal carcinomas: (1) keratinizing squamous cell carcinoma, (2) non-keratinizing differentiated carcinoma, and (3) undifferentiated carcinoma. Treatment for all three of types of is usually the same.
Other cancers may form in the nasopharynx. One type are lymphomas, which begin in immune system cells. Another type are adenocarcinoma and adenoid cystic carcinoma, which begin in the minor salivary glands. These are less often found in the nasopharynx, but nearby.
Risk Factors, Diagnosis and Stages
Risk Factors & Symptoms
Following are common risk factors for the disease:
- Drinking large amounts of alcohol
- Smoking tobacco
Other risk factors include:
- Chinese or Asian ancestry
- Exposure to the Epstein-Barr virus (The Epstein-Barr virus has been associated with certain cancers, including nasopharyngeal cancer and some lymphomas.)
- Diets with very high salt content such as cured fish and meat
- Family history of nasopharyngeal cancer
- Vitamin deficiencies and poor oral hygiene
- Exposures to substances like formaldehyde or wood dust
These and other symptoms may be caused by nasopharyngeal cancer. Other conditions may cause the same symptoms. Consult a doctor if you have any of these problems:
- A lump in the nose or neck
- A sore throat
- Trouble breathing or speaking
- Nosebleeds or mouth bleeds
- Trouble hearing
- Pain or ringing in the ear
- Double vision
Biomarker testing/Molecular testing of the tumor
Your doctor may want to test your tumor for P16 or HPV. In certain kinds of head and neck cancer (oropharyngeal squamous cell carcinomas), knowing this test result will help your doctor decide on the treatment that is best for you. The tumor may also be assessed for the Epstein-Barr Virus (EBV). This can cause cancers in the nasopharynx (upper part of the throat behind the nose).
Your doctor will do a physical exam and ask you many questions. It is important to describe how you have been feeling and any changes you have noticed, such as pain, difficulty swallowing, mouth or throat sores, or changes in your voice.
Your doctor may order some of these tests:
- Endoscopy - A thin, lighted tube is inserted through the nose to look at the back of your nose and throat. This may be done at the doctor’s office, often after using numbing spray.
- Biopsy - A sample of tissue is removed to check for cancer.
- Fine needle aspiration - This is a type of biopsy done with a small needle to see if you have cancer. It is often used to assess lumps in the neck.
- Fiberoptic endoscopic evaluation of swallowing test (FEES) - A thin, lighted tube is inserted through your nose and down your throat so that the health care provider can watch how you swallow from inside.
- Biomarker testing/Molecular testing of the tumor - Your doctor may want to test your tumor for P16 or HPV. In certain kinds of head and neck cancer (oropharyngeal squamous cell carcinomas), knowing this test result will help your doctor decide on the treatment that is best for you. The tumor may also be assessed for the Epstein-Barr Virus (EBV). This can cause cancers in the nasopharynx (upper part of the throat behind the nose).
Your doctor may also use the following diagnostic tests:
- CT Scan
- PET or PET-CT Scan
- Modified barium swallow studies (a series of x-rays taken after you swallow a barium drink)
If you are diagnosed with nasopharyngeal cancer, your doctor needs to know how aggressive the cancer is, whether it has spread, and if it has, where it has spread in the body. Staging is a careful attempt to do this, and staging information will help guide treatment decisions.
Nasopharyngeal cancers are staged with the AJCC (American Joint Committee on Cancer) system. This is a rating system that assigns a measurement for TNM:
- T = Tumor characteristics, based on imaging tests. This describes how big the tumor is and how far into the nasopharynx the cancer has grown.
- N = Lymph Nodes involved. This defines if and how cancer has spread to lymph nodes in the neck.
- M = Metastases. This explains if and where cancer has spread (into other organs in the chest, liver or bones).
Each of these factors are defined with a number ranging from 0 (or x – meaning it’s very early disease) to 4 a, b, c (meaning the disease is very advanced). After this, the cancer’s Stage is defined with a scale from “Stage 0” (for very early signs of cancer), to Stage IV a, b or c (for very advanced cancers).
Abnormal cells are found in the lining of the nasopharynx. The cells are only found on the top layer of nasopharynx (Tis). No lymph nodes are affected (N0), nor are other parts of the body (M0).
Cancer has formed and is found in the nasopharynx. Or, it has spread from the nasopharynx to the oropharynx and/or to the nasal cavity (T1). No lymph nodes are affected (N0), nor are other parts of the body (M0).
The cancer is found in the nasopharynx and it has spread from the nasopharynx to the oropharynx, to the nasal cavity, or to tissue in the upper part of the throat (T1 or T2). Cancer may have spread to one or more lymph nodes on one side of the neck and/or to lymph nodes behind the pharynx (N1). The affected lymph nodes are six centimeters or smaller. No other part of the body or bone is affected (M0).
The primary cancer is more advanced. It may have grown into the oropharynx or nasal cavity (T1). It has grown to tissues with in the upper part of the throat (T2). Or, it has grown into the sinuses or bones nearby (T3). The cancer has also spread to lymph nodes in the neck or behind the throat, but they are not larger than 6cm across (N2). Cancer has not spread to other parts of the body (M0).
Stage IV is divided into stages IVA and IVB
- Stage IVA: The primary cancer is very advanced. It may have spread to the cranial nerves, the hypopharynx (bottom part of the throat), the main salivary gland or tissues around the eye (any T, up to T4). Cancer may also have spread to one or more lymph nodes on one or both sides of the neck and/or to lymph nodes behind the pharynx, or in the shoulder area. The affected lymph nodes are six centimeters or smaller (any N). These cancers have not spread to other parts of the body (M0)
- Stage IVB: These cancers have spread to other parts of the body such as distant metastases to the lungs or bone (any T, any N, and M1)
Treatment and Side Effects Management
Surgery is sometimes used for nasopharyngeal cancer that does not respond to radiation therapy. If cancer has spread to the lymph nodes, the doctor may remove lymph nodes and other tissues in the neck.
If a neck dissection is necessary, you may experience side effects. The most common side effects of any neck dissection are numbness of the ear, weakness when raising the arm above the head, and weakness of the lower lip. These side effects are caused by injury during the operation to certain nerves that supply these areas. You may also get swelling, or lymphedema, to the area of the neck above the surgical cut in the neck.
Immunotherapy is a treatment that helps your immune system fight the cancer better. One immunotherapy drug, known as a checkpoint inhibitor, has been approved for nasopharyngeal cancer:
- Toripalimab-tpzi (Loqtorz®)