The term cancer encompasses a very large group of illnesses that are all characterised by abnormal cell growth; cancer cells divide and grow in an uncontrolled manner and in any part of the body.
Cells normally grow and divide to form new cells as, and when, the body requires them. When a normal cell ages or is damaged, it dies and is replaced by a new cell. In the case of cancer, however, the body loses control over this highly ordered process. As the cells become increasingly abnormal, the old or damaged cells survive instead of dying and new cells develop when they are not required. This uninterrupted cell division forms masses, otherwise known as tumours.
How does Cancer develop?
The initial cause of cancer can be found in our genes, which are responsible for controlling cell reproduction. This genetic origin can be either hereditary or the result of structural changes affecting the genes throughout an individual’s lifetime, whether spontaneously or in association with environmental factors.
Cancer cells differ from healthy cells because they feature molecular alterations that modify their normal function. This means the normal cycle of cell growth and death is broken, resulting in uncontrolled cell division and the accumulation of excess cells in the body which form a tumour.
In the case of benign tumours, there is an increase in the number of cells, but they continue to have a normal structure and function.
Malignant tumours can spread to nearby tissues. Some cells can grow in neighbouring organs beyond where the initial tumour developed, spreading by means of blood vessels or the lymphatic system. This process is called metastasis.