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Cancer is a disease that's caused by cells in the body growing out of control and making new abnormal cells.
Every part of our body is made up of cells that fit together like building blocks. Cells of the same type group together to make different kinds of tissue, for example fat, muscle, bone, nerves and blood (a liquid tissue).
Each cell has a control centre (called a nucleus) where DNA (deoxyribonucleic acid) is stored. The nucleus tells the cell what to do and contains our genes (which we inherit from our parents).
Cells are too small to see with your eye, but doctors can examine them with powerful microscopes and tell what type they are.
Usually cells grow, divide to make new cells, and eventually die off. Millions of cells die every second, but millions of others divide to replace them.
Cancer develops when something goes wrong with the cell and it grows and divides in an uncontrolled way. It makes lots of cells that don’t die off in the way normal cells do. These cells eventually make up a tumour (lump). Or in a blood cancer (which is called leukaemia) there won’t be a tumour, but lots of abnormal cells will be produced.
Diagram of cells forming a tumour
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Sometimes a tumour can turn out to be benign (which means it’s not a cancer). A tumour that is a cancer is sometimes called a malignant tumour.
Doctors can tell whether a tumour’s benign or malignant by removing a small piece of tissue (called a biopsy) and examining the cells under a microscope.
This animation shows how blood cells are made, how they function and some of the possible effects of cancer treatment on your blood.
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We don’t know what causes most cancers, especially the types that young people get. Doctors and scientists are researching this.
Remember that for most cancers:
Risk factors are things that can increase the chances of developing some cancers. Here are some examples:
Cancer in teenagers and young adults is pretty rare. Most cancers are diagnosed in people over 65. Although there are over 200 different types of cancer, certain cancers are more likely to affect teenagers and young people. Some of these are:
If you’ve been told you have cancer, you’ll probably feel scared, shocked and not sure what it all means. Getting support from family, friends and the doctors and nurses looking after you can really help.
Finding out a bit more about the type of cancer| you have can also help. Understanding it better might make seem it a bit less scary. And you can also learn some of the things you can do to help yourself.
Many cancers in teenagers and young people can be cured with treatment. The type of treatment you get depends on different things, such as the type of cancer, where it is and whether it’s spread to another part of the body.
The main treatments are:
Other anti-cancer drugs can also be used. These are called targeted therapies (biological therapies or monoclonal antibodies).
Cells can sometimes spread from where the cancer started (the primary cancer) and go to other parts of the body. These cells can eventually make another cancer, which is called a secondary cancer or a metastasis.
Cells can spread in different ways:
It’s common to have treatment to reduce the risk of the cancer spreading or coming back (called adjuvant treatment). For example, radiotherapy and chemotherapy are often given after surgery. This is to get rid of any cancer cells that might be left behind, or any that have spread to other parts of the body.
Content last reviewed: 1 June 2012
Next planned review: 2014
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
Macmillan have helped me get to where I want to be in five years' time Emmanuel, Macmillan intern
Macmillan have helped me get to where I want to be in five years' time
Emmanuel, Macmillan intern
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.
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© Macmillan Cancer Support 2013
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