What is Cancer

Cancer is a group of diseases that involve the uncontrolled division of cells in the body. This rapid cell growth produces a cluster of cells called a tumour, which interferes with normal tissue structure and function.

There are two kinds of tumours: benign and malignant.

Benign tumours are composed of slow-growing cells contained within a layer of tissue. These tumours can be removed effectively with surgery. They usually do not reappear.

Malignant tumours typically contain more rapid growing; actively moving cells that tend to invade other tissues. The movement of malignant cells from their original site to other body areas is called metastasis.

Some cancers, like leukaemia, do not form tumours. Instead, these cancer cells involve the blood and blood-forming organs and circulate through other tissues where they grow.

Different types of cancer can behave very differently. For example, lung cancer and breast cancer are very different diseases. They tend to grow at different rates and respond to the various form of treatment differently. It is for this reason that people with cancer need treatment that is tailored to their particular kind of cancer.

The sooner a cancer is found and treatment begins, the better the chances are for living for many years and minimising the toxicities, dislocation and therapy.

Cancer is a disease that starts in our cells. Other terms for cancer are tumours and neoplasms, although these terms can also be used for non-cancerous growths.

Our bodies are made up of millions of cells, grouped together to form organs or tissues such as the lungs, the liver, muscles and bones. Genes inside each cell order it to grow, work, reproduce and die. Normally these orders are clear, our cells obey and we remain healthy. Sometimes a cell's instructions get mixed up and it behaves abnormally. After a while groups of abnormal cells form lumps or tumours.

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

Malignant tumour cells are able to invade the tissues around them and spread to other parts of the body. Cancerous cells that spread to other parts of the body are called metastases. The first sign that a malignant tumour has spread is often swelling of nearby lymph nodes, but cancer can metastasize to almost any part of the body. Malignant tumours can be dangerous. It is important to find them and treat them quickly, before they spread.

Although a number of cancers share risk factors, most cancers have a unique set of risk factors that are responsible for their onset. Some cancers occur as a direct result of smoking, dietary influences, infectious agents or exposure to radiation, while others may be a result of inherited genetic faults. For many cancers, the causes are unknown. While some of the causes are modifiable through lifestyle changes, some others are inherited and cannot be avoided.

It is important to realise that cancer is not a single disease with a single cause and a single type of treatment. There are more than 200 different kinds of cancer, each with its own name and treatment.

By Cancer Types we mean cancers occurring in different parts of the body. Cancers are named after the part of the body where they start. For example, cancer that starts in the colon but spreads to the liver is called colon cancer with liver metastases.

For more information on the types of cancer, please click on the links below: