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Cancer comes in many shapes and sizes, and how it affects the body varies greatly. But we'll talk you through the basic definition of cancer and what causes it.
Cancer is a term used to describe a group of illnesses all having certain common characteristics. These characteristics include an over-growth of cells that forms a tumour. There are over 200 different types of cancer, each with a specific name, treatment and chance of being cured.
What all cancers have in common is the lack of normal cell growth, which can result in serious health problems.
This video tells you all about cancer, the different types and causes. The information in this video was correct as of 1st August 2012.
Tumours cause medical problems in two ways:
To better understand what cancer is and how it occurs, we'll discuss how cells grow and reproduce normally.
Cell multiplication is normal. We all start life as just one single cell, the ovum, which is fertilized by sperm and begins to multiply, producing more cells. These cells grow and mature to become nerve cells, muscle, blood cells or connective tissue (e.g., skin).
Groups of these different types of cells then come together to form our organs (eyes, ears, legs, lungs, skin, etc). Each of our organs is made up of many different types of cells and each cell has a particular function within that organ; the cells work in co-operation with each other to make the organ work effectively.
In the heart, for example, specific cells called cardiac muscle-cells pump blood. However, nerve cells are also located in the heart. These cardiac nerve cells are needed to conduct the electrical signals to produce each contraction. Therefore, many different types of cells must work in co-operation with each other in order for an organ to work effectively.
Occasionally, cells within an organ die off or wear out and new cells then replace them. This growth of new cells is a highly complex and tightly regulated process.
With cancer, for one reason or another, the growth of new cells becomes faulty. When a cancer cell begins to grow, rather than just replacing the cells that have been damaged or lost, it multiplies out of control, taking over the organ. In some cases the cancer cell grows so much it forms a mass of cells called a tumour. This tumour can cause health problems by blocking internal ducts, or by pressing against other organs, preventing them from working properly.
Tumours can be either benign or malignant:
Once the cancer spreads, the cells migrate to many other distant sites and organs in the body. Multiple growths may occur, affecting many parts of the body, eventually causing multiple organs to fail. These growths are known as secondary cancers or metastasis.
Organs or parts of the body that have a rich blood or lymph supply are the most likely places where malignant growths appear. These organs include the lungs, the liver, bone marrow and lymph nodes.
Carcinomas are malignant tumours that arise from cells lining the surfaces of the body. For example, a cancer of the lining of the stomach is termed a carcinoma, as is cancer arising from cells lining the breast ducts. These are often just called cancers.
Sarcomas are malignant tumours that arise out of cells in the supporting structures of the body (e.g. bone, muscle and cartilage).
Leukaemia, lymphoma and myeloma are all malignancies that arise from blood cells or from cells that go to make up blood. These cancers are also known as haematological malignancies.
Freephone 1800 200 700 to talk to a specialist cancer nurse
It's open Monday-Thursday from 9am to 7pm and Friday from 9am to 5pm
National Cancer Helpline
Freefone 1 800 200 700
Talk to a specialist nurse
Have you used the Irish Cancer Society's cancer information services by phone, Daffodil Centre, email, social media or this website? A UCD research team is helping us to evaluate so that we can improve those services.
I just completed a year in St James’s Hospital, working as a pharmacy intern. My research looks at drugs commonly used for different diseases, but that may also be useful in cancer.
Pharmacy & Therapeutics Department, St. James Hospital