Cancer

There are more than 200 types of cancer, each with its own symptoms and treatments. As it’s not possible to look at each cancer specifically, we have prepared a brief overview of cancer – how it develops, its diagnosis and current treatments - and included contact details for organisations that provide more detailed information and specialist support.

What is cancer?

All cancers are diseases where cells grow out of control, instead of following normal development and growth.

When cells grow out of control, they often form a lump that you may not be aware of called a tumour. This is a characteristic of most cancers apart from leukaemia. 

Leukaemia is cancer of the bone marrow and affects its ability to produce and release, in appropriate numbers, normal red and white blood cells into the blood stream.

A tumour can be benign or malignant. 

A benign tumour is one that cannot spread to other parts of the body.

With a malignant tumour, cells can break off from where the tumour starts and spread to other parts of the body.

A primary tumour is where the cancer starts and is made up of cells from that part of the body. So a primary lung cancer is made up of lung cancer cells.

Tumours formed when cells spread away from where they started and grow in other parts of the body are called secondary tumours.  A secondary tumour is sometimes called a metastasis. It is made up of the same cells as the primary cancer; for example when breast cancer spreads to the lungs, the lung tumour is made up of breast cancer cells. 

Tumours can be found in many parts of the body.  The site of a primary tumour can predict the likely location of secondary tumours and sometimes a secondary tumour causes symptoms before the primary tumour is detected.

A cell can become cancerous when there are changes to the genes in that cell –the genes may become damaged or be defective in some way. Several changes to genes in a cell are needed before it becomes cancerous and this usually happens over a period of time.