What is a rare cancer?

Rare cancers affect a small number of people. Doctors might also call a cancer rare if it starts in an unusual place in the body. Or if the cancer is an unusual type and needs special treatment.

What makes a cancer rare?

There are more than 200 different types of cancer, including leukaemias and lymphomas. They develop from the different types of cells in different parts of the body. Some of these cancers are common, such as breast, bowel, prostate and lung cancer. Some types are uncommon and some are rare.

Experts have different ideas about what makes a cancer rare. Some say that a type of cancer is rare if doctors diagnose fewer than 2 in 100,000 people each year.

Other experts say it is rare if fewer than 6 in 100,000 people are diagnosed each year.

Worldwide rare cancers make up 22 out of every 100 (22%) of cancers that are diagnosed each year. This means that 1 in 5 people diagnosed with cancer has a rare type.

Research also shows that about 1 in 3 people with a rare cancer have a particularly rare type.

Subtypes of more common cancers

Doctors and researchers are learning more and more about cancer, leukaemia and lymphomas. They are looking at particular features that divide some cancers into subtypes. They think that some of these subtypes are rare.

Doctors treat some rare subtypes in the same way as other cancers of that type. Other subtypes get treated differently. For example, they treat small cell cancer of the cervix in a different way to most other cervical cancers.

Finding information

It can be hard to find useful information about a rare type of cancer. Ask your doctor or specialist nurse if they know of any suitable information. You could ask about the best term to use if you want to look for information online.

Check if we have information on your cancer. Type the name in the search box at the top of each page. Or look for your cancer type on our A to Z list of cancer types.

You can also contact the Cancer Research UK nurses on 0808 800 4040 9am to 5pm Monday to Friday

Coping and isolation

Many people feel isolated if they have a rare type of cancer. It might take longer to get a diagnosis and to start treatment. And you may not know anyone else with this type of cancer.

You might need to go to a specialist hospital for treatment. This could involve travelling a bit further than your local hospital. But it can be reassuring to know that a specialist team is caring for you. You are also more likely to meet someone else with your cancer type.

Give yourself time to cope. Ask your doctor or nurse what help and support are available to you and your friends and family.

Last reviewed: 
23 Aug 2019
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    R Pillai and K Jayasree
    Indian Journal of Medical Research 2017 January;145(1):17-27

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  • What is a Rare Cancer? 
    G Eslick
    Hematology/Oncology Clinics of North America Year.2012, 26 (6), pp. 1137-1141 

  • Rare cancers are not so rare: the rare cancer burden in Europe.

    G Gatta and others

    European Journal of Cancer. 2011 November; 47(17):2493-511.