What is cancer?

These pages give you some basic information about cancer. Our bodies are made up of billions of tiny living cells. These cells grow and divide naturally, producing more cells as they are needed to keep the body healthy. Old cells die naturally and are replaced by new ones.

Sometimes this orderly process can go wrong. The genes that tell a cell what to do can get damaged, usually by factors in our lifestyle or environment, for example cigarette smoke or strong sunlight. This can cause cells to multiply out of control, forming new and different cells when the body does not need them. These uncontrolled, abnormal cells are termed “malignant”, and the disease they cause is called cancer.

More information about cancer

There are many types of cancer, usually named after the organ or tissue where they start. The abnormal, unwanted cells may form a lump, called a “tumor” (or solid cancer). Or they may be dispersed throughout the body, as with blood cancers or cancers of the lymph system (called non-solid cancers).

When tumors continue to develop, they start to attack nearby organs. Cancer cells may also break away from the tumor and attack other parts of the body. This spread of cancer cells from one part of the body to another is called “metastasis”.

If cancer cells spread to organs that we need to survive, they can damage the normal functioning of these organs, and this may eventually be fatal.

Even though the success of cancer treatment has greatly improved and about 50% of cancers can now be cured, cancer is still a huge medical challenge. You can find more information about cancer and cancer treatment on this site.

Use the menu on the left if you would like more information about cancer