In this section: Unknown Primary Cancer

CANCER of an unknown primary

What do we mean by 'Cancer of an Unknown Primary'? Cancer of Unknown Primary in the head and neck region occurs when the origin of the cancer is unknown, but is found to have spread to the lymph nodes in the neck. If it's not the cancer type you're looking for, please explore the information about other types of Head and Neck Cancers.

All the information in this section is available in a PDF.
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​1. Treatment options for Cancer of Unknown Primary

Your cancer care team will discuss the treatment options available for treating Cancer of Unknown Primary. This is also a good time to consider if you would like a second opinion.

The treatment most suited to each person depends on many factors, including: 

  • the number and size of the lymph nodes that are affected

  • personal factors  (e.g. age, general health and treatment history)

  • treatments available (and whether any clinical trials are available)

  • your preferences for treatment. 

The treatment options for Cancer of Unknown Primary are:

  • Surgery (often combined with radiotherapy and chemotherapy)

  • Radiation therapy (often combined with chemotherapy)

2. Surgery for Cancer of Unknown Primary

Some common types of surgery that can be used for Cancer of Unknown Primary in the head and neck area are:


This involves removing the enlarged cancerous lymph nodes, together with other lymph nodes in the same region of the neck. 
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This involves removing the tonsils, if there are signs of cancer in the tonsils or other lymph nodes in the neck. It can also help with diagnosing the type of cancer.
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3. Radiation Therapy for Cancer of Unknown Primary

For Cancer of Unknown Primary, radiation therapy may be used to treat the lymph nodes affected by cancer with or without the primary site(s) that it may likely have come from. The most common approach for cancer of unknown primary is called external beam radiation. This is where the radiation is applied from outside of the body.

Radiation therapy can be used in the following ways:


This is when radiation therapy is used on its own without surgery. Definitive radiation therapy may be targeted to one side of the neck area (unilateral), containing the cancerous lymph nodes, or both sides of the throat (bilateral) to treat all possible areas of primary cancer. Typically, radiation therapy is delivered daily (but not on weekends) over 7 weeks. Chemotherapy may be added to the radiation therapy (chemoradiation)


This is when radiation therapy is given after surgery and is used as an additional treatment to kill any cancer that may not have been removed during surgery. Adjuvant radiation therapy may also be given in combination with chemotherapy (called chemoradiation).


In cases where a cure is not possible, radiation therapy is used to relieve symptoms of advanced cancer of unknown primary. Symptoms that may require palliative radiation therapy include pain, bleeding, breathing and swallowing difficulties.

4. Chemotherapy for Cancer of Unknown Primary

Chemotherapy works by destroying or damaging cancer cells. For head and neck cancers, chemotherapy is usually given into a vein through a needle with a catheter (tube) attached.

Usually chemotherapy is used in combination with radiation therapy to make the radiation therapy more effective. It is usually given once a week or once every 3 weeks throughout the duration of radiation therapy. Unlike chemotherapy for many other cancers, most patients do not lose their hair or have severe nausea and vomiting.

Once your treatments end, you will have regular follow-up appointments so that your doctor can check your recovery, make sure the cancer has not returned and monitor and treat any side effects that you may have.

  1. Head and Neck Cancer Australia Resources 
  2. External Links to other Head and Neck Cancer Resources