There are many processes that control a cell’s growth and division, each of which can go wrong. As a general rule-of-thumb, several of these control mechanisms need to be damaged before a cell becomes cancerous.

The abnormal cell grows without following the rules that directed it. Some cancers grow quickly; others grow slowly. As the cancer grows, it can invade normal organs causing normal body functions to be compromised or stopped. Tumours can squeeze organs or block passages. This will eventually cause symptoms or problems. Cancer also tends to spread (metastasise) to other parts of the body.

Cancer happens in stages. Typically, these stages are:

Stage I, the simplest form, indicates that the tumour is small and confined to the organ or tissue where it began. The best chance for cure is when the tumour is still in Stage I.

Stage 2 means the tumour has spread to surrounding tissues.

Stage 3 means the tumour has spread into surrounding tissues and lymph nodes.

Stage 4 signifies more extensive spread, often to many organs or parts of the body.

The earlier the stage when diagnosed, the greater the chance of being cured.