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Cancer - what is it?

cancer; tumour; malignant; benign; treatment; chemotherapy; radiotherapy; surgery;


What is cancer?

Cancer is the abnormal uncontrolled growth of cells in the body, which can interfere with the normal functions of the body, and can spread from one part of the body to another.

  • Our bodies are made up of millions of tiny cells. Cells are the building blocks of life. If you think of your body as a house, cells are the bricks that make up that house.
  • As cells grow they change to perform different jobs. Skin cells, for example, grow into what you see as skin.
  • When new cells are needed they reproduce by splitting (dividing) in two.
  • How many cells are made in any one spot is controlled by the genes inside the cells, and also by contact with cells around them.
  • Cancer forms when this division goes wrong. The signals that usually stop normal growth when there are enough cells for some reason do not work.
    • The cells keep on dividing when they are not needed,
    • The immune system does not recognise that the cells are behaving abnormally, so it does not destroy them.
  • The cancerous cells divide over and over, until they take over and crowd out the healthy cells.
  • When this happens, a tumour is formed. There are two types of tumours – benign and malignant (cancer).
    • Benign tumours are not cancer, as they do not spread around the body.
    • Malignant tumours are cancer. They can spread into local tissues, or around the body.

What causes cancer?

There is a lot of debate about what actually causes cancer. There are some things (called ‘risk factors’) which increase the chance of a person getting cancer.

  • Smoking, for instance, causes lung cancer (but, there are some people who have smoked and never get lung cancer).
  • Exposure to ultraviolet (UV) radiation – too much time in the sun (which contains UV rays) has been linked with skin cancer.
  • Alcohol – heavy drinkers are at greater risk of developing certain types of cancer.
  • Exposure to cancer-causing agents ('carcinogens') in the environment is linked to various types of cancer. For example, some foods (eg. smoked foods) contain more carcinogens.
  • What we eat and drink can have an affect on cancer. Having a healthy diet with lots of fresh fruit and veggies, and having a 'normal' weight is a way of reducing the chances of getting some cancers. A 'normal' weight is not too fat, but also not too thin.
  • Some people inherit an increased risk of getting cancer – cancer is partly a genetic problem.
  • Cancer also happens more often in people whose immune system has been damaged (which is why people with HIV/AIDS get more cancers than other people).
  • Often, people who seem to be at risk don’t get cancer and those who live very healthy lifestyles sometimes do.

Cancer can happen to anyone. It is important to remember this, as it is not anyone’s fault if they get cancer.


  • For some cancers, early detection (finding the cancer very early, while it is small and has not spread) can increase the chances of a cure.
  • For some cancers there is now a high likelihood that treatment will lead to a cure, but for some other cancers, treatment is mostly about helping the person to feel comfortable.
  • Many cancers are in between - some but not all people can be cured.
  • How well a cancer responds to treatment depends on the type of cancer.

There are several ways that cancers can be treated.

  • Surgery is often used to remove all or part of a tumour. This process is sometimes used with other treatments, such as radiotherapy and chemotherapy. In some cancers, like leukaemia, surgery cannot be used because the cancer cells are in many parts of the body.
  • Radiotherapy is high-energy x-rays directed at the cancer, to kill cancer cells.
  • Chemotherapy is where drugs are used to destroy the cancer cells. Chemotherapy affects other fast growing cells such as bone marrow cells and hair cells. That is why sometimes cancer patients’ hair falls out.
  • Hormone therapy is the treatment of cancer by blocking the hormones that a cancer needs to grow.
  • Immunotherapy is a newer treatment, which boosts the person’s immune system to help it fight the cancer.
  • Bone marrow transplants are used when bone marrow cells have been deliberately destroyed during treatment, because the bone marrow is making the cancer cells. Healthy bone marrow produces red and white blood cells.
  • Pain relief and managing nausea (feeling sick). Some cancers cause pain, but the treatment of cancer can be painful and sometimes it causes people to feel very ill. Pain management can often be very successful. Some pain relief might sometimes make a person feel drowsy. Patients need to make sure they talk in depth about possible pain and ways to manage it with their doctor or nurse.

Alternative treatments

Alternative means anything that is different from normal. Alternative therapies are cancer treatments that differ from the treatments listed above ('orthodox' medical treatments). These treatments are usually used side-by-side with the treatments listed above.

Most of the alternative models of treatment are based on one idea - if our bodies and minds are at peace and in harmony, then the body can heal itself. Unfortunately, with cancer, this is not always possible.

The main techniques used to achieve this are:

  • meditation, relaxation, listening to music – these and other techniques can help by slowing the person down and stopping negative thoughts.
  • diets that cut out some foods that may slow healing – it is important to discuss diet changes with a dietitian during chemotherapy and radiotherapy, as these treatments can have major effects on digestion.
  • counselling - getting more information and empowering the person to make their own decisions.
  • exercise - keeping fit and healthy in ways that are not dominated by "illness".
  • developing a positive attitude – this can be very hard when you are feeling ill. Sometimes trying to be positive can become a stress in itself.

The right alternative treatments can help people cope with cancer and the effects of medical treatments, and improve general health – but they are not the only answer.


South Australia



Now what 
Now What has been developed by CanTeen, the Australian Organisation for Young People Living with Cancer. Now What has been developed by a team of people including CanTeen staff and young people whose lives have been affected by cancer.

Victorian Adolescent and Young Adult Cancer Service 

Further reading

National Cancer Institute (USA):


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The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor, or ring the Youth Healthline on 1300 13 17 19 (local call cost from anywhere in South Australia).
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