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  • Treatment for cancer of unknown primary


    When tests have been unable to find the primary cancer, a diagnosis of CUP is given. This is often a difficult time and it can be hard to accept that the primary cannot be found. Some people may feel relieved that the tests are over and that the focus can now be on treatment options.

    Your doctors will recommend treatment based on:

    • what will give you the best outcome
    • the location of the secondary cancer
    • test results
    • how likely it is to be a certain type of cancer
    • your general health
    • your preferences.

    The most common treatment for CUP is chemotherapy. You may also have radiotherapy, hormone therapy, surgery or targeted therapies. Different types of treatment may be combined.

    For many people, CUP is diagnosed at an advanced stage and treatment is unlikely to cure it. However, treatment may be able to control the cancer and improve your symptoms. It is possible that treatment may make you feel better and also help you live longer. This is called palliative treatment.


    Chemotherapy is the treatment of cancer with anti-cancer (cytotoxic) drugs. It aims to kill cancer cells while doing the least possible damage to healthy cells.

    Medical oncologists and sometimes other specialists prescribe chemotherapy to shrink tumours, and to relieve symptoms caused by the cancer. It can also be used in combination with radiotherapy or surgery to try to kill any local collections of cancer cells in the body. Different cancer cells respond to different chemotherapy drugs. People with CUP may have a combination of drugs.

    Generally, chemotherapy is given by injecting the drugs into a vein (intravenously), often through a drip. The drugs circulate through the bloodstream and can kill cancer cells throughout the body (systemic treatment). Some types of chemotherapy are taken by mouth as tablets.

    Chemotherapy is given in courses known as cycles. Each cycle consists of a treatment period followed by a recovery period. You may be able to have treatment as an outpatient, but sometimes a short stay in hospital is required.

    The number of treatment cycles you have depends on your situation. With CUP, it is recommended that your doctors test how the cancer responds to the chemotherapy after two or three cycles. This will allow you to weigh up the benefits of continuing against the effect on quality of life.

    Side effects of chemotherapy

    Most chemotherapy drugs cause side effects. Different drugs have different side effects. Your medical oncologist or nurse will discuss them with you.

    The most common side effects include feeling sick (nausea), vomiting, mouth sores, tiredness, loss of appetite, diarrhoea, and some thinning or loss of hair from your body and head. Most side effects are temporary, and can be prevented or reduced.

    Chemotherapy weakens the immune system, making it harder for your body to fight infections. You will have regular blood tests to check your immune system. If your temperature rises to 38°C or above while receiving chemotherapy, contact your medical team or hospital immediately.

    For more information about chemotherapy, call Cancer Council 13 11 20 or you can download the booklet Understanding chemotherapy.


    Radiotherapy uses x-ray beams to kill cancer cells. For most people with CUP, the purpose of radiotherapy is to relieve symptoms, such as bleeding, difficulty swallowing, breathlessness, blocking of the intestines, compression of blood vessels or nerves by tumours, and pain caused by cancer spreading to the bones.

    You will have an x-ray of the treatment area to help with planning your treatment. To ensure that the same area is treated each time, the radiation therapist will make a few small dots (tattoos) on your skin that may be temporary or, in some cases, permanent. Talk to your radiation oncologist if you are concerned about the tattoos.

    You may have external or internal radiotherapy. External radiotherapy is given from a machine outside the body. For internal radiotherapy, a radiation source is put inside the body on or near the cancer. Radiotherapy treatments are painless. The total number of treatments and their duration will depend on your situation. You might need only a couple of treatments, or you may need them every weekday for several weeks.

    Some people with localised squamous cell carcinoma in the lymph nodes of the neck may have a combination of chemotherapy and radiotherapy (chemoradiation) to try to treat the disease.

    Side effects of radiotherapy

    The side effects of radiotherapy depend on the area of the body being treated and the dose of radiation.

    Common side effects include nausea, loss of appetite, diarrhoea, tiredness and shortness of breath. It can also make your skin dry and itchy in the area treated. Your skin may look red or sunburnt.

    Side effects tend to develop as you go through treatment, and most improve or go away after treatment is finished. Talk to your doctor or nurse about ways to manage them.

    For more information about radiotherapy, call Cancer Council 13 11 20 or you can dowload the booklet Understanding radiotherapy.

    Hormone therapy

    Hormones are substances that occur naturally in the body, but some cancers are stimulated by particular hormonesfor example, breast cancer by oestrogen. Hormone therapy uses hormones made in a laboratory (synthetic) to block the effect of the natural hormones that are helping the cancer to grow.

    If tests show that the CUP may have started as a cancer that is hormone dependent, your doctor might suggest hormone therapy. The treatment may be given as tablets or injections. It is sometimes used with other treatments, e.g. to shrink a tumour before surgery.

    Side effects of hormone therapy

    The side effects vary depending on the hormones you are given.

    General side effects include tiredness, nausea, diarrhoea, constipation, appetite changes, weight gain, mood changes, hot flushes, pain in the joints, thinning of the bones, hot flushes (for women) and erection problems (for men).

    Targeted therapies

    Targeted therapies are a new group of drugs that destroy or stop the growth of cancer cells while minimising harm to healthy cells. It is not yet clear how useful targeted therapies are for CUP, but clinical trials are testing combinations of chemotherapy and targeted therapies.

    Most targeted therapies are injected into a vein, but some are given by mouth as tablets.


    Surgery is a common treatment for many types of cancer if they are found at an early stage. With CUP, the cancer has already spread beyond the site where it started, so surgery may not be used as a treatment or it may remove only some of the cancer.

    If the cancer is found in only one area (e.g. in the lymph nodes in the neck, underarm or groin), it may be possible to remove it with an operation. Surgery may be followed by radiotherapy or chemotherapy to kill any cancer cells left in the body. Sometimes surgery can help with symptomsfor example, to relieve pain caused by the cancer pressing on a nerve or organ.

    Side effects of surgery

    Some people experience pain after surgery but this is often temporary. Talk to your doctor or nurse about painkillers.

    If you’ve had lymph nodes removed, you may develop lymphoedema. This is swelling caused by a build-up of fluid in part of the body, usually in an arm or leg.

    For more information about lymphoedema, call Cancer Council 13 11 20 or you can dowload the booklet Understanding lymphoedema.

    Palliative treatment

    Many people with CUP receive palliative treatment, which can be used at any stage of advanced cancer to improve quality of life. Palliative treatment aims to slow the spread of cancer and manage symptoms without trying to cure the disease. It is one aspect of palliative care, in which a team of health professionals aim to meet your physical, emotional, practical and spiritual needs. Palliative care is not just end-of-life care and does not mean giving up hope. Rather, it is about living for as long as possible in the most satisfying way you can. It also provides support to families and carers.

    It is best to make contact with the palliative care team as early as possible. You can find out what the different team members do and work out which services might be useful now or in the future.

    For more information about palliative treatment, call Cancer Council 13 11 20 or download the booklet Understanding palliative care and Living with advanced cancer.

    This website page was last reviewed and updated in February 2018.

    Information reviewed by: A/Prof Linda Mileshkin, Medical Oncologist, Peter MacCallum Cancer Centre, VIC; Dr Sarwan Bishnoi, Medical Oncologist, Adelaide Cancer Centre, SA; Dave Clark, Consumer; Dr Jan Maree Davis, Area Director, Palliative Care Service, Calvary Health Care and St George Hospital, NSW; Linda Tompsitt, Cancer Nurse 13 11 20, Cancer Council WA; Catherine Trevaskis, Gastrointestinal Cancer Specialist Nurse, The Canberra Hospital, ACT.

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