What is rare cancer?

For a cancer to be rare, it means fewer than 6 in 100,000 people in the UK are diagnosed with it each year.

Common, less common and rare cancers

There are hundreds of different types of cancer. Over half of all cancers diagnosed in the UK (53%) are made up of just four cancers. These are cancers of the lung, breast, bowel and prostate.

Then there are less common cancers, such as ovarian cancer and melanoma. About one in four cancers diagnosed in the UK (27%) are less common cancers.

Then there are rare cancers. About one in five people with cancer in the UK (20%) have a rare cancer. About one in three people who have a rare cancer have a very rare type. Very rare cancers affect fewer than 1 in 100,000 people each year.

Proportions of common, less common, rare and very rare cancers
Proportions of common, less common, rare and very rare cancers

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There are 198 different types of rare cancer, but only a small number of people are diagnosed with each type. Rare cancers include cancers you may have heard of, including thyroid cancer, acute lymphoblastic leukaemia (ALL) and mouth cancer. There are also many very rare cancers most people will not be familiar with.

The diagram below shows where in the body rare cancers might develop. About one in five rare cancers affect the blood and lymphatic system. These include leukaemias and some types of lymphoma.

Parts of the body that are affected by rare cancers
Parts of the body that are affected by rare cancers

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Reasons that a cancer might be rare

  • Most cancers start in certain types of cells, such as skin cells and the cells lining the organs of the body. A rare cancer might start in a different type of cell than usual, for example in a bone cell.
  • A rare cancer might be a subtype of a more common cancer. For example, non-Hodgkin lymphoma (NHL) is one of the 10 most common types of cancer. But there are many subtypes of NHL. Some of these are very rare.
  • The cancer may be in an unusual part of the body for that type of cancer. For example, melanoma (a type of skin cancer) that starts in the eye.
  • It may affect a child or teenager. All cancers in children and teenagers are considered rare cancers.

Coping with a rare cancer

Having a rare cancer can mean extra challenges. The cancer may take longer to diagnose. Finding the best treatment may involve travelling to a specialist centre some distance from home.

Many people with cancer feel isolated, but this can be even more of a problem for someone who has a rare cancer. Because fewer people have the same type of cancer, it can be difficult meeting people in a similar situation. If the cancer does not behave in a similar way to a common cancer, you may feel family and friends don’t understand what you are coping with

Getting information about a rare cancer, how it is treated and what to expect can also be difficult.

Follow the links above to go to pages with more information about what can help.

Back to Rare cancers

Types of rare cancer

We have information on many types of rare cancers. Use our A-Z list to find out more.

Treating rare cancer

If you have a rare cancer, your treatment will usually be planned by a team of specialists.