What is cancer?

Cancer is a disease of the body’s cells. Our bodies are made up of millions of cells which normally grow and are renewed in a controlled way, and we remain healthy. However, sometimes this control is lost. This may be due to an abnormality in the cells, such as a genetic mutation or exposure to a carcinogen (cancer causing agent) and the cells start to multiply unchecked instead of just renewing themselves. A solid group of these cells is called a tumour or growth.

Tumours can be either benign (non-cancerous) or malignant (cancerous). Benign tumour cells stay in one place in the body and are not usually dangerous. 

Malignant tumour cells may travel through the lymphatic system (the body’s drainage system) to lymph nodes or through blood to other parts of the body. 

This spread of a cancer from one organ to another organ or part of the body not directly connected with it is called metastasis or metastatic cancer. Cancer actually refers to about 100 different diseases as cancerous cells can arise from almost any type of tissue cell. 

Cancer is not contagious and cannot spread from person to person, however factors can lead to an increased risk of developing cancer such as smoking, sedentary lifestyle, obesity, alcohol consumption, some viruses and some environmental or genetic risk factors.

Cancer, unlike many other diseases, can develop at any stage in life and in any body organ. Each person’s cancer has a different cause, diagnosis method, prognosis, treatment and care need.

New Zealand has an increasing number of people diagnosed with cancer mainly because of population growth and people living longer. Most cancers occur in older people, but because of screening programmes, improved detection and treatments fewer people now die of cancer in New Zealand. For more information about cancer statistics check out: