Nasopharyngeal Cancer: Symptoms, Causes, and Treatment

Nasopharyngeal cancer is a common subtype of head and neck cancers. These cancers differ significantly from other head and neck malignancies in terms of their etiology, epidemiology, histopathology, biological behavior of the disease, and treatment. Therefore, nasopharyngeal cancers should be considered separately from other head and neck malignancies. This type of cancer is difficult to diagnose early, and its treatment typically involves radiotherapy and chemotherapy.

What is Nasopharyngeal Cancer?

The nasopharynx is a region located behind the nose, at the base of the skull, also known as the nasopharyngeal area. It connects the nose, the back of the throat, and the larynx. Air taken in through the nose first passes through the nasopharynx, then moves down the back of the throat to the larynx, and subsequently travels down the trachea to the lungs. Uncontrolled growth of cells in the nasopharynx leads to the formation of nasopharyngeal cancer.

Several different types of cancer can develop in the nasopharynx. The most common types of nasopharyngeal cancer are as follows:

• Nasopharyngeal Carcinoma: The most common type of nasopharyngeal cancer is nasopharyngeal carcinoma. This cancer is characterized by the uncontrolled growth of epithelial cells lining the surface of the nasopharyngeal area, forming tumor tissue. Nasopharyngeal carcinoma has three subtypes: non-keratinized undifferentiated (undifferentiated), non-keratinized differentiated (differentiated), and keratinized squamous cell. While the treatment methods for these three subtypes are the same, the causes of the cancer and the response to treatment may differ among the subtypes.
• Lymphoma: Lymphoma, characterized by the excessive proliferation of lymphocytes (immune system cells), can also affect the nasopharynx.
• Minor Salivary Gland Cancers (Adenocarcinoma, Adenoid Cystic Carcinoma, etc.): These cancer types, originating from cells in the minor salivary glands, are typically found in the nasal and oral regions.

What are the Risk Factors?

Despite the studies conducted, the genetic changes that play a role in cancer development are not well understood. Among environmental factors, dietary habits, cooking with wood fire, air pollution, chemical vapors, and previous nasal (Epstein-Barr virus) infections are considered risk factors. However, while there is strong evidence for the role of all three factors in the etiology of laryngeal cancer, it suggests that multiple factors, through complex carcinogenesis mechanisms, play a role together.

The frequency of the disease gradually increases during adolescence, leading to a peak distribution in the 40-50 age range. It is also noted that there is a second increase in some regions during adolescence. Nasopharyngeal cancer is seen four to five times more often in men than in women.

What are the Symptoms of Nasopharyngeal Cancer?

The symptoms of nasopharyngeal cancer may initially resemble those of more common diseases, such as upper respiratory tract infections or chronic nasal congestion. For this reason, early-stage diagnosis may not be possible based solely on symptoms, and a diagnosis may be delayed. Furthermore, the disease may not show any symptoms in its early stages.

The most common symptoms of nasopharyngeal cancer include:

• Swelling in the lymph nodes (glands) in the neck region
• Nasal congestion
• Ringing in the ears
• Hearing loss (unilateral hearing loss is more concerning)
• Persistent ear infections that do not improve with treatment
• Sore throat
• Headache
• Blood in the saliva
• Nosebleeds

What Causes Nasopharyngeal Cancer?

Cancer develops due to one or more genetic mutations, leading to faster cell division, expansion into surrounding tissues, and spread to other parts of the body (metastasis). In nasopharyngeal carcinomas, these mutations mainly occur in epithelial cells, and the cancer originates from these cells. The most common cause of nasopharyngeal carcinoma is the Epstein-Barr Virus (EBV). However, many environmental, racial, and genetic factors also play significant roles in its etiology.

Some risk factors that increase the likelihood of developing nasopharyngeal cancer include:

• Gender: Nasopharyngeal cancer is more common in men than in women.
• Age: Nasopharyngeal cancer can occur at any age but peaks during two age periods: initially in the 20s and 30s and later in the 50s and 60s.
• Cured Foods: Foods such as salted fish and preserved canned foods contain various chemicals in the cooking vapors. Inhaling these chemicals can progress to the nasopharynx and increase the risk of cancer. Early exposure to these preserved and cooked foods further increases the risk.
• Epstein-Barr Virus: EBV is a common virus that causes flu-like illnesses in the body. Infectious mononucleosis is also caused by EBV. This virus plays a role in the formation of a group of cancers, including nasopharyngeal cancer.
• Family History: People with a family history of nasopharyngeal cancer are at a higher risk of developing it.
• Smoking: Smoking increases the risk of nasopharyngeal cancer.
• Race: Nasopharyngeal cancer is more common in East Asian countries, particularly China, and among people who have migrated from these regions to other parts of the world.

Is Early Diagnosis Possible?

Through regular annual health check-ups, suspicious lesions and/or patient complaints can be examined early.

How is the Diagnosis Made?

To diagnose nasopharyngeal cancer, the patient's detailed medical history is first taken, and any symptoms are inquired about. It is also investigated whether the patient carries any risk factors for cancer. Afterward, a physical examination is conducted. During the examination, the presence of any noticeable lumps in the neck area can be significant for nasopharyngeal cancer.

To examine the nasopharynx more closely and in detail, nasal endoscopy may be performed. In this method, a thin tube with a light source and a camera at its end is inserted through the nose to the nasopharynx. This allows for the inspection of the area from the nose to the nasopharynx to detect any potential tumors. Nasal endoscopy is typically performed without anesthesia or under local (regional) anesthesia. If a structure that suggests cancer is observed during the procedure, a biopsy sample is taken from that tissue. The pathological examination of the tissue sample will determine whether the mass is benign or malignant (cancerous). If the tissue sample is compatible with nasopharyngeal cancer, additional parameters such as the subtype and stage of the cancer can also be determined through pathological examination.

After the diagnosis of nasopharyngeal cancer, imaging methods are used to assess how far the cancer has spread to surrounding tissues and whether it has metastasized to other parts of the body. Imaging techniques such as Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), and Computed Tomography (CT) may be used.

The stage of the cancer is determined based on the pathology results and the information obtained from imaging methods. This staging is crucial for determining the treatment protocol for the patient.

What Are the Stages of the Disease?

Good staging is the most important point in deciding whether to proceed with curative or palliative treatment. It is essential to perform distant metastasis screenings with a thorough evaluation. In 5-10% of patients, distant metastasis is present at the time of diagnosis. Therefore, the number of examinations, especially related to the stage of local and regional disease, may be increased. In advanced nodal disease (N3a, N3b), distant metastasis screenings are extremely important.

How is Nasopharyngeal Cancer Treated?

Radiotherapy (Radiation Therapy)
Radiotherapy, also known as radiation therapy, is a method that uses radiation to destroy cancer cells. For the treatment of nasopharyngeal carcinoma, external beam radiotherapy is commonly used. In this method, the patient lies on a flat table, and a machine that moves around them directs radiation precisely to the tumor site.

For small nasopharyngeal cancers, radiotherapy alone may be sufficient. However, for larger tumors, radiotherapy and chemotherapy may need to be administered together.

In internal radiation therapy or brachytherapy, the radiation source is placed inside or very close to the tumor. Brachytherapy is especially used for recurrent nasopharyngeal cancers.

Radiotherapy to the head and neck area may cause side effects such as skin redness, dry mouth, hearing loss, difficulty swallowing, and mouth sores. If side effects develop, medications may be given to alleviate the symptoms.

Chemotherapy
Chemotherapy is a treatment method that uses chemicals to kill cancer cells. Chemotherapy drugs can be administered orally or intravenously.

Radiotherapy and chemotherapy are frequently used together for the treatment of nasopharyngeal cancer. For patients who can tolerate it, using both methods simultaneously enhances the effect of the treatment. However, because the side effects of both methods may occur at the same time, simultaneous treatment may not be suitable for every patient. In these cases, the treatment plan is usually to administer radiotherapy first, followed by chemotherapy.

Surgery
Surgery is not typically used as the first step in the treatment of nasopharyngeal cancer. If the tumor recurs in both the nasopharynx and neck after radiotherapy and/or chemotherapy, surgery may be performed using either endoscopic or open techniques for the nasopharyngeal tumor. For the neck area, a salvage neck dissection is performed to remove cancerous lymph nodes.

Nasopharyngeal cancer is a significant cancer type that is commonly seen in societies, like ours, where tobacco use is prevalent. The fact that the disease does not present symptoms in the early stages can create a challenge for early diagnosis and treatment. In the presence of swelling in the neck, nasal congestion, nosebleeds, and especially unilateral hearing loss that does not respond to treatment, it is advisable to visit an Ear, Nose, and Throat doctor at the nearest health center for necessary examinations.

Treatment Complications
Treatment complications can be divided into those related to radiation therapy and chemotherapy. Radiation therapy-related complications can be assessed as acute and late complications. Acute reactions that occur during radiation therapy or within three months after treatment are most commonly seen in rapidly dividing tissues (mucosa, skin, bone marrow, etc.) that are within the radiation treatment area. In addition to treatment parameters (fraction dose, total dose, total treatment duration, and radiation volume, etc.), factors such as the patient's age, general condition, type of surgery performed before radiation or chemotherapy, and other factors that affect acute reactions must also be considered.

Is it Possible to Prevent?

Healthy eating, a good lifestyle, and regular physical activity will help strengthen the immune system and ensure effective overall body defense.