Oropharyngeal cancer

Pronunciation

It is pronounced OR-oh-fuh-RIN-jee-ul KAN-ser

Definition

Cancer that forms in tissues of the oropharynx (the part of the throat at the back of the mouth, including the soft palate, the base of the tongue, and the tonsils).

Type

Most oropharyngeal cancers are squamous cell carcinomas.

=Risk factors

• A history of smoking cigarettes for more than 10 pack years and other tobacco use.
• Heavy alcohol use.
• Being infected with human papillomavirus (HPV), especially HPV type 16.
• The number of cases of oropharyngeal cancers linked to HPV infection is increasing.
• Personal history of head and neck cancer.
• Chewing betel quid, a stimulant commonly used in parts of Asia.

Signs and symptoms

Signs and symptoms of oropharyngeal cancer include a lump in the neck and a sore throat or difficulty swallowing. These and other signs and symptoms may be caused by oropharyngeal cancer or by other conditions.

• A sore throat that does not go away.
• Trouble swallowing.
• Trouble opening the mouth fully.
• Trouble moving the tongue.
• Weight loss for no known reason.
• Ear pain.
• A lump in the back of the mouth, throat, or neck.
• A white patch on the tongue or lining of the mouth that does not go away.
• Coughing up blood.
• Sometimes oropharyngeal cancer does not cause early signs or symptoms.

Tests

Tests that examine the mouth and throat are used to diagnose and stage oropharyngeal cancer. The following tests and procedures may be used:

1. Physical exam and health history: An exam of the body to check general signs of health, including checking for signs of disease, such as swollen lymph nodes in the neck or anything else that seems unusual.
2. Neurological exam: A series of questions and tests to check the brain, spinal cord, and nerve function.
3. PET-CT scan: A procedure that combines the pictures from a positron emission tomography (PET) scan and a computed tomography (CT) scan.
4. CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the head, neck, chest, and lymph nodes, taken from different angles.
5. MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body.
6. Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. A fine-needle biopsy is usually done to remove a sample of tissue using a thin needle.

Other procedures and tests

The following procedures may be used to remove samples of cells or tissue:

Endoscopy: A procedure to look at organs and tissues inside the body to check for abnormal areas. Laryngoscopy: A procedure in which the doctor checks the larynx (voice box) with a mirror or a laryngoscope to check for abnormal areas.

If cancer is found, the following test may be done to study the cancer cells:

HPV test (human papillomavirus test): A laboratory test used to check the sample of tissue for certain types of HPV infection, such as HPV type 16.

Prognostic factors

Certain factors affect prognosis (chance of recovery) and treatment options. The prognosis depends on the following:

• Whether the patient has HPV infection of the oropharynx.
• Whether the patient has a history of smoking cigarettes for ten or more pack years.
• The stage of the cancer.
• The number and size of lymph nodes with cancer.
• Oropharyngeal tumors related to HPV infection have a better prognosis and are less likely to recur than tumors not linked to HPV infection.

Stages

After oropharyngeal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the oropharynx or to other parts of the body. There are three ways that cancer spreads in the body. Cancer may spread from where it began to other parts of the body.

The following stages are used for HPV-positive oropharyngeal cancer:

1. Stage I
2. Stage II
3. Stage III
4. Stage IV

The following stages are used for HPV-negative oropharyngeal cancer: Stage 0 (Carcinoma in Situ)

1. Stage I
2. Stage II
3. Stage III
4. Stage IV

Spreading of cancer

There are three ways that cancer spreads in the body. Cancer can spread through tissue, the lymph system, and the blood:

• Tissue = The cancer spreads from where it began by growing into nearby areas.
• Lymph system - The cancer spreads from where it began by getting into the lymph system.
• Blood - The cancer spreads from where it began by getting into the blood.
• Cancer may spread from where it began to other parts of the body. When cancer spreads to another part of the body, it is called metastasis.

Metastatic cancer

Many cancer deaths are caused when cancer moves from the original tumor and spreads to other tissues and organs

Teams of providers

• Head and neck surgeon.
• Radiation oncologist.
• Plastic surgeon.
• Dentist.
• Dietitian.
• Psychologist.
• Rehabilitation specialist.
• Speech therapist.

Treatment modalities

There are different types of treatment for patients with oropharyngeal cancer. Patients with oropharyngeal cancer should have their treatment planned by a team of doctors with expertise in treating head and neck cancer. Four types of standard treatment are used:

• Surgery
• Radiation therapy
• Chemotherapy
• Targeted therapy
• Immunotherapy

Surgery

Surgery (removing the cancer in an operation) is a common treatment of all stages of oropharyngeal cancer. A surgeon may remove the cancer and some of the healthy tissue around the cancer. After the surgeon removes all the cancer that can be seen at the time of the surgery, some patients may be given chemotherapy or radiation therapy after surgery to kill any cancer cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.

New types of surgery, including transoral robotic surgery, are being studied for the treatment of oropharyngeal cancer. Transoral robotic surgery may be used to remove cancer from hard-to-reach areas of the mouth and throat. Cameras attached to a robot give a 3-dimensional (3D) image that a surgeon can see. Using a computer, the surgeon guides very small tools at the ends of the robot arms to remove the cancer. This procedure may also be done using an endoscope.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. External radiation therapy uses a

Intensity-modulated radiation therapy (IMRT): IMRT is a type of 3-dimensional (3-D) radiation therapy that uses a computer to make pictures of the size and shape of the tumor. Thin beams of radiation of different intensities (strengths) are aimed at the tumor from many angles. Stereotactic body radiation therapy: Stereotactic body radiation therapy is a type of external radiation therapy. Special equipment is used to place the patient in the same position for each radiation treatment. Once a day for several days, a radiation machine aims a larger than usual dose of radiation directly at the tumor. By having the patient in the same position for each treatment, there is less damage to nearby healthy tissue. This procedure is also called stereotactic external-beam radiation therapy and stereotaxic radiation therapy. In advanced oropharyngeal cancer, dividing the daily dose of radiation into smaller-dose treatments improves the way the tumor responds to treatment. This is called hyperfractionated radiation therapy. Radiation therapy may work better in patients who have stopped smoking before beginning treatment. If the thyroid or pituitary gland are part of the radiation treatment area, the patient has an increased risk of hypothyroidism (too little thyroid hormone). A blood test to check the thyroid hormone level in the body should be done before and after treatment.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy).

See Drugs Approved for Head and Neck Cancer for more information. (Oropharyngeal cancer is a type of head and neck cancer.)

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells. Targeted therapies usually cause less harm to normal cells than chemotherapy or radiation therapy do. Monoclonal antibodies are a type of targeted therapy being used in the treatment of oropharyngeal cancer.

Monoclonal antibodies

Monoclonal antibodies are immune system proteins made in the laboratory to treat many diseases, including cancer. As a cancer treatment, these antibodies can attach to a specific target on cancer cells or other cells that may help cancer cells grow. The antibodies are able to then kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion. They may be used alone or to carry drugs, toxins, or radioactive material directly to cancer cells.

Cetuximab is a type of monoclonal antibody that works by binding to a protein on the surface of the cancer cells and stops the cells from growing and dividing. It is used in the treatment of recurrent and metastatic oropharyngeal cancer.

Immunotherapy

Immunotherapy is a treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. This cancer treatment is a type of biologic therapy.

PD-1 is a protein on the surface of T cells that helps keep the body’s immune responses in check. PD-L1 is a protein found on some types of cancer cells. When PD-1 attaches to PD-L1, it stops the T cell from killing the cancer cell. PD-1 and PD-L1 inhibitors keep PD-1 and PD-L1 proteins from attaching to each other. This allows the T cells to kill cancer cells.

Pembrolizumab and nivolumab are types of PD-1 inhibitors being studied in the treatment of oropharnygeal cancer.

Treatment side effects

• Treatment for oropharyngeal cancer may cause side effects.

Follow up

Follow-up tests may be needed.

Gallery

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  Oropharyngeal Cancer

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  RT Mask Oropharyngeal cancer

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  IMRT Oropharyngeal cancer

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  OPC Transverse radiation contour

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  Sarcoid like lesion in a nuchal lymph node in a case of oropharyngeal squamous cell carcinoma, HE

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