Understanding cancer

You may just have found out that you have cancer - and it isn't easy to get your head around. There are lots of different types, names and techie terms used to describe what's going on in your body and how you're feeling.

It's no wonder that you can feel overwhelmed and don't know where to start with all the information out there. And it's the same for your friends and family too. They may want to know how they can help you get through this. It is also possible that you will be wondering how you can get your family and friends through it as well.

That's where Teenage Cancer Trust comes in. This section is designed to provide lots of information for you, your friends and family - to help you understand about cancer. Where we do not have the expertise we can point you safely in the right direction. From explaining the different types, to how to talk to your family and friends, and those close to you.

What is cancer?

Cancer is a disease of the cells in the body. The organs and tissues of the body are made up entirely of tiny building blocks called cells. Cancer is a disease that causes an uncontrolled growth of abnormal cells in the body. There are over 200 different types of cancer.

The centre of a cell is called the nucleus. Inside the nucleus are the genes; genes are really bits of code that carry information. Genes control the cell, they decide when it will reproduce, what it does and when it will die. If a gene is damaged or lost we call this a mutation. The basic cause of cancer is due to faulty or ‘mutated’ genes.

Normally, genes ensure that cells grow and reproduce in a controlled way. If the cell system goes wrong for any reason the normal response is that the gene tells the cell to die. Rarely, the gene becomes faulty and rather than ending the life of an abnormal cell the genes will allow the abnormal cells to keep on dividing and multiplying until a lump called a tumour is formed. This is how cancer develops.

For many cancers in young people, we simply don’t know what causes this damage. Sadly it is believed that many cancers can’t be prevented. But the good news is that there are precautions we can take to decrease our chances of getting some kinds of cancer later in life.

What are the most common types of cancer?


Breast cancer, bowel cancer, lung cancer and prostate cancer are the most common cancers found in adults in the UK. In fact, they are so common that out of all of the 200 + cancers that exist, the above makeup 54% of all cancers diagnosed in the UK.

Breast cancer is the most common cancer in the UK despite the fact that it is rare in men. It makes up 31% of all cancers diagnosed in women in the UK. The next most common cancer in the UK is lung cancer which affects marginally more men than women. Prostate cancer is the most common cancer found in men in the UK making up 25% of all diagnosis in males.


The most common types of cancer diagnosed in children are leukaemia, brain and central nervous system tumours and lymphomas. These account for 68% of all cancers diagnosed in the age group 0-14 years old.

Leukaemia forms the most commonly diagnosed cancer in children accounting for 30% of all cancers in this age group. Acute lymphoblastic leukaemia is by far the most common type of leukaemia to affect children; it accounts for around 78% of all leukaemias diagnosed in children.

Teenagers and Young Adults

Cancer in children and in older adults can behave differently to cancer in teenagers and young adults. As a teenager or young adult your body changes and grows very quickly, so teenagers can get some of the rarest and most aggressive forms of cancer.

The most common cancers in young people aged 15 to 24 are: Lymphomas, 21% Carcinomas, 20% Germ cell tumours, 15% Brain, other CNS and intracranial tumours, 14% Malignant melanoma, 11% Leukaemias, 9% Bone tumours, 5% Soft tissue sarcomas, 4% Other and unspecified, 1%

The most common cancer in young men are germ cell tumours (testicular cancer) (27%)

The most common cancer in young women is carcinomas (thyroid, cervix, bowel and ovary) (31%)

More than 80% of young people aged between 13 and 24 diagnosed with cancer survive their disease for at least five years. The survival rate is slightly higher in females (84%) than males (81%)

What causes cancer?


Age is the biggest risk factor. The older a person is, the more likely they are to develop cancer. DNA damage is thought to occur in every single person several thousands of times every day. This is not something to worry about because fortunately, our bodies are very good at repairing this damage. However, the longer a person lives, the more unrepaired faults are gathered in their DNA. Over time, these faults can cause cancer. In fact, nearly two thirds of all cases of cancer occur in people aged 65 or over. Living an unhealthy lifestyle makes it more difficult for our bodies to repair faults and so over time makes the risk of damaged DNA, and therefore cancer, much higher. Avoiding harmful substances like tobacco smoke and the suns rays will help keep your body healthy so that it may repair any faults. Lifestyle Choices

Over 40% of cancers that occur in the UK are caused by ‘lifestyle choices’; mainly tobacco use, alcohol consumption, the food we eat, being overweight, not exercising, infection and exposure to radiation and sun damage. Often, cancer that is the consequence of lifestyle choice is avoidable.

Smoking is the biggest preventable cause of cancer in the world; 1 in 5 cancers in the UK are caused by smoking and in the UK smoking kills 5 times more people than road accidents.

Smoking can cause lung cancer, mouth, oesophagus, cervical and bowel.

Over exposure to the sun’s UV rays can damage the DNA in skin cells and can cause cancer. The UVA rays in sunbeds are particularly harmful as they are ten times stronger than the midday sun. Using a sunbed for the first time, before the age of 35, increases your risk of developing melanoma skin cancer by 59%.

Day to day environment and carcinogens

A carcinogen is a substance that causes cancer. There are many things that fall into this category such as tobacco smoke, sun rays and asbestos (a material that was used in the past for purposes such as loft insulation and car manufacturing).

For a carcinogen to cause cancer, a person must have had a large amount of exposure to it. Some people have jobs that regularly expose them to dangerous chemicals or carcinogens. For example, it has been found that there has been large incidents of bladder cancer found in people working in chemical dye factories. Genetic makeup

For a cell to become cancerous there needs to be a number of genetic mutations within it. Some people are what’s called ‘genetically predisposed’ and at a greater risk of developing cancer. This means these people are born with certain genetic mutations in their cells.

Being born with genetic mutations does not necessarily mean that a person will develop cancer. It just means they are statistically more likely to develop cancer within their lifetime than someone who has not been born with these mutations. Viruses

There are certain viruses that can increase a person’s risk of developing certain types of cancer. A good example of this is the Human Papilloma Virus (HPV.) There are around 100 different strains of HPV but only around ten are thought to be dangerous. Although exposure to HPV rarely leads to cancer, doctors do believe that every person who has had invasive cervical cancer has been exposed to HPV virus.

As well as having strong links with cervical cancer, exposure to HPV increases a person’s likelihood of developing other cancers of the genital and anal area. HPV is also linked to oropharyngeal cancer and nonmelanoma skin cancers.

Other viruses that are linked to cancer are Hepatitis B and C viruses. These are thought to increase a person’s risk of developing primary liver cancer. The Epstein-Barr Virus is thought to have links to Lymphoma.

Family Support Network

Family Support Networks have been developed to provide support throughout the cancer journey. They focus on the needs of the whole family – if loved ones are supported the young person in turn will be supported.



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