MEN'S HEALTH MATTERS:Cancer is the term used for diseases in which abnormal cells divide without control, writes THOMAS LYNCH
Q What exactly is cancer and what are the main types of cancer? When people talk about secondaries, what do they mean? Are there any lifestyle changes that I can make to help decrease my chances of developing cancer?
A The body is made up of many types of cells and all cancers begin in these cells – the body’s basic unit of life. Under normal circumstances cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy.
When cells become old or damaged, they die and are replaced with new cells.
This orderly process can go wrong and the genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division.
“Cancer” is the term used for diseases in which abnormal cells divide without control and are able to invade other tissues. The cancer cells continue to grow and crowd out normal cells and may form a mass of tissue called a tumour. Although there are many kinds of cancer, they all have this “out-of-control” growth of cells in common.
Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start – for example, cancer that begins in the bladder is called bladder cancer. Different kinds of cancer can behave very differently. For example, lung cancer, prostate cancer and breast cancer are very different diseases. They grow at different rates and respond to different treatments.
It is important to remember that all of our cells have similar structures and share a majority of their functions. Cancers may be categorised based on the functions/locations of the cells from which they originate. The following terms are commonly used to distinguish tumours of different origin.
Carcinoma: a tumour derived from epithelium which is a type of tissue that covers the surface of our skin and organs such as the urinary tract, digestive tract and airways. Since these tissues are often rapidly dividing to replace lost cells and are often exposed to environmental insults such as chemicals and radiation from the sun, this is the most common cancer type and represents about 80-90 per cent of all cancer cases reported.
Sarcoma:cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
Leukaemia:cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.
Lymphoma and myeloma: cancers that begin in the cells of the immune system, the complex group of organs and cells that defends the body against infections and other diseases.
Central nervous system cancers:cancers that begin in the tissues of the brain and spinal cord.
Sometimes cancer cells break away from a tumour and spread to other parts of the body through the blood or lymph system.
Lymph nodes are regional collection centres in the lymphatic system. Fluid from the areas surrounding the lymph nodes drains into the lymph nodes just like smaller streams fuse to form a larger river. These cancer cells can settle in new places and form new tumours. When this happens, it is called metastasis. Cancer that has spread in this way is called metastatic cancer or secondaries.
Even when cancer has spread to a new place in the body, it is still named after the part of the body where it started. For example, if prostate cancer spreads to the bones, it is still called prostate cancer.
Although national cancer control efforts encourage healthy lifestyles, promote cancer screening, increase access to quality cancer care, and improve quality of life for cancer survivors, there are changes that you can make to your own lifestyle to help decrease your chances of developing cancer.
There is a strong link between tobacco use and many cancers. You can quit smoking and greatly reduce your risk of developing cancer and other serious diseases. Eating a healthy diet may reduce your risk of developing cancer and other serious illnesses. Physical activity is also associated with a reduced risk of colon, breast and other cancers. Increasing your physical activity by taking a 30- minute walk three times per week may help reduce your risk of developing cancers.
You should talk to your GP about appropriate cancer screening tests.
- This weekly column is edited by Thomas Lynch, consultant urological surgeon, St James's Hospital, Dublin
- If you have a men's health question which you would like answered, please e-mail healthsupplement@irishtimes.com