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Survival statistics for cancer of unknown primary (CUP)

Men and woman discussing unknown primary cancer

Survival statistics for cancer of unknown primary (CUP). There is information about 

 

A quick guide to what's on this page

Statistics and outlook for cancer of unknown primary (CUP)

Outlook means your chances of getting better. Doctors call this prognosis. It is not possible even to give an overview of statistics or prognosis for CUP because it varies so much from one person to another. Further down this page we have tried to give you some guidance on factors affecting outcome and special situations, where doctors know from experience where the cancer is likely to have started and how things might turn out.

A wide range of cancer types can first show up as unknown primary. All these cancers will tend to develop differently and grow at different rates. Some will be more likely than others to spread further to other parts of the body. Some types of cancer may be curable, even though they have spread before they were diagnosed.

The outlook also depends on the type of cancer you have and on how far it has spread before you have any treatment. It will depend on the way your cancer responds to the treatment you are given.

It is best to talk to your own specialist, who should be able to give you some broad guidelines. Even then, it will be very difficult for your specialist to be accurate and you will only be able to get a best guess at how the cancer will develop. It will become clearer how your cancer is going to behave as you have treatment.

 

CR PDF Icon You can view and print the quick guides for all the pages in the Treating CUP section.

 

 

General cancer statistics

This page has quite detailed information about the survival rates for different stages of unknown primary cancer (CUP). People ask us for this information but not everyone diagnosed with cancer wants to read it. If you are not sure whether you want to know at the moment, you can always come back to it later.

The statistics here are intended as a general guide and can't tell you what is likely to happen in your individual case.

 

Factors affecting outcome

The outlook depends on the type of cancer you have and on how far it has spread and whether you have any treatment. It will also depend on how well your cancer responds to the treatment you have.

For unknown primary cancers, specialists have put together a list of factors that indicate whether a cancer is more or less likely to be curable. These are only a guide and you will need to talk about your particular situation with your own specialist. You may be more likely to have a curable cancer if you

  • Are under 50 years old
  • Have germ cell markers called HCG or AFP that suggest you have a germ cell tumour (a testicular cancer)
  • Have granules in the cancer cells called neuroendocrine granules
  • Have signs of very fast tumour growth (because this can indicate a lymphoma that is likely to respond well to treatment)
  • Have a cancer that responds very well to chemotherapy or radiotherapy
  • Have cancer cells in the lymph nodes in your neck, suggesting the primary is a squamous cell head and neck cancer

The most important factor that affects outcome is how sensitive the particular cancer cells are to the treatment you have. Other factors that can affect the success of treatment are your general health and level of fitness. Some people are not fit enough to have more intensive treatments so their chances of successful treatment can be lower.

It is important to realise that most cancers are chronic conditions. That means that it is unusual for them to grow quickly and you usually become unwell slowly over a period of months or even years. If your cancer is not a type that is curable, your specialist may give you treatment designed to try to keep the cancer under control for as long as possible.

It is best to talk to your own specialist, who should be able to give you some broad guidelines about your outlook. Even then, it will be very difficult for your specialist to be accurate and you will only be able to get a best guess. It will become clearer how your cancer is going to behave as you have treatment. The treatment could work well and slow the cancer down. Your doctor will be able to tell you that within a few months. If the cancer is a fast growing one that is going to come back quite quickly, this will also become clear as you go through your treatment and then have check ups.

 

Special situations

In some situations doctors know from experience where the primary cancer is most likely to have started. Although everybody's situation with an unknown primary cancer is always unique, we have included the following information to give you some guidance about how things may turn out. As always, you will need to talk this over with your specialist to put your own case in perspective. 

It is important for people with cancer of unknown primary to make sure that they attend their follow up appointments. The primary cancer may be discovered later on, and further treatment could then be possible.

These special situations are

Lymph nodes in the neck

If your cancer has appeared as one or more enlarged lymph nodes in your neck, your doctor may suspect a cancer of the head and neck or a lung cancer. It is well worth trying to find out where the cancer started. Up to 2 out of 3 people with a type of head and neck cancer called squamous cell cancer will survive for at least 3 years after treatment to try to cure their cancer.

Melanoma in a single group of lymph nodes

About 5 in 100 (5%) people with melanoma don't have an obvious primary cancer site. If the cancer is only in one group of lymph nodes it is a stage 3A melanoma. Removing the whole group of affected nodes can cure the cancer. Obviously the success of treatment depends on whether the melanoma has spread anywhere else beforehand. But the outlook is quite good if it hasn't. Between 57 and 73 out of 100 people (57 to 73%) diagnosed with stage 3A melanoma will survive for 5 years or more after diagnosis. Between 50 and 67 out of 100 people (50 to 67%) will survive for more than 10 years after diagnosis.

Lymph nodes under one arm

About half of all women with unknown primary who have cancer in the lymph nodes under one arm will have breast cancer. The outlook depends on the number of lymph nodes affected by cancer. The fewer nodes affected the better the outlook. About 80 out of 100 (80%) people with breast cancer who have between 1 and 3 lymph nodes affected will survive for 5 years or more after diagnosis. Your doctor may do tests on your cancer cells to help decide whether you have breast cancer or not.

Lymph nodes in the groin

If the cancer has spread to one or more lymph nodes in your groin, the primary site could be in the legs, anus, scrotum, vulva, vagina or bladder. You will need extensive tests to try to find the primary tumour. Many people can live for years after surgery to remove the lymph nodes and then close follow up.

 

More detailed statistics

If you would like to read more about survival rates and other statistics for unknown primary cancer, go to our CancerStats page:

https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/cancer-of-unknown-primary-cup

 

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Updated: 4 August 2014