The organs and tissues on our body are made up of cells. Cells in different parts of the body may look and work differently but most reproduce themselves in the same way. Most of the cells in our body live for a period of time and are then gradually replaced with new cells. Our body has the ability to identify cells that have not been made properly and then correct any defects. This allows the cell to return to being a fully working, normal cell again.
If the body cannot correct an abnormal cell, then there is a mechanism in place to kill the cell. Sometimes these abnormal cells cannot be fixed or 'killed off'. They develop and grow without your body’s control. Sometimes they grow into a collection of abnormal cells called a tumour. Tumours can be benign or malignant.
Benign tumours are not cancerous because they do not spread to beyond the original tumour growth area; however, they may still cause problems by pressing on the surrounding organs. They can be removed by an operation and do not usually cause any further problems.
A malignant tumour is a growth (group) of cancer cells. Cancer is a general term to describe uncontrolled, abnormal growth and division of cells. Malignant tumours have the ability to spread beyond the original tumour growth area. Cancer cells have the ability to travel from one part of the body to another via the blood or lymphatic system (a system of thin tubes and nodes that is part of the body’s immune system). Newly formed tumours are called metastasis or secondary cancer. Cancer cells are also able to invade and destroy other tissue around them. Nowadays many cancers are caught before they have spread.