Cancer is a group of conditions where the body's cells begin to grow and reproduce in an uncontrollable way. These cells can then invade and destroy healthy tissue, including organs.
Cancer sometimes begins in one part of the body before spreading to other parts. This process is known as metastasis.
How common is cancer?
Cancer is a common condition. Around 29,000 new cases of cancer are diagnosed each year in Ireland. More than one in three people will develop some form of cancer during their lifetime.
There are hundreds of different types of cancer. The most common cancers in Northern Ireland (excluding non-melanoma skin cancer) are: