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Cancer of unknown primary

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Treatments for cancer of unknown primary

If you have cancer of unknown primary (CUP), your healthcare team will create a treatment plan just for you. It will be based on your needs and may include a combination of different treatments. When deciding which treatments to offer for CUP, your healthcare team will consider:

  • the type of CUP
  • the amount of differentiation of the cancer cells
  • whether it is favourable-risk or poor-risk CUP
  • where and how many different places cancer is found
  • prognosis
  • performance statusperformance statusThe measure of how well a person is able to perform ordinary tasks and carry out daily activities.
  • where the cancer may have started (called the primary site)
  • your overall health
  • your age
  • your preferences for treatment

You may be offered the following treatments for CUP.


Chemotherapy is the main treatment for CUP. Usually 2 or more chemotherapy drugs are used. The healthcare team will offer drugs based on the type of CUP that you have and how it responds to treatment.

Chemotherapy may not be offered if you are in poor health or if you have a type of CUP that will not respond to chemotherapy.

Radiation therapy

External beam radiation therapy may be offered for CUP. It is usually used to relieve pain and control symptoms (called palliative radiation therapy). It may be given after surgery to reduce the risk that the cancer will come back, or recur.


Chemoradiation combines chemotherapy with radiation therapy. The 2 treatments are given during the same time period. Chemoradiation is sometimes offered for squamous cell CUP that is found in lymph nodes in the neck.

Hormonal therapy

Some types of CUP may respond to hormonal therapy, which is a treatment that adds, blocks or removes hormones. For women, doctors may offer hormonal therapy if they think that the primary site is the breast. For men, it may be offered if doctors think the prostate is the primary site.

Hormonal therapy can also be used to shrink tumours, relieve pain or control the symptoms of some types of advanced CUP.


The types of surgery offered will depend on where the CUP is found. For example, surgery may be used to completely remove a single tumour in one organ.

If you can’t have or don’t want cancer treatment

You may want to consider a type of care to make you feel better rather than treat the cancer itself. This may be because the cancer treatments don’t work anymore, they’re not likely to improve your condition or they may cause side effects that are hard to cope with. There may also be other reasons why you can’t have or don’t want cancer treatment.

Talk to your healthcare team. They can help you choose care and treatment for advanced cancer.

Follow-up care

Follow-up after treatment is an important part of cancer care. You will need to have regular follow-up visits, based on your type of CUP and how you have responded to treatment. These visits allow your healthcare team to monitor your progress.

Clinical trials

Very few clinical trials in Canada are open to people with cancer of unknown primary. Clinical trials look at new and better ways to prevent, find and treat cancer. Find out more about clinical trials.

Questions to ask about treatment

To make the decisions that are right for you, ask your healthcare team questions about treatment.


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