Cancer is the second leading cause of death in the world and was responsible for 8.8 million deaths in 2015 alone. Globally, nearly 1 in 6 deaths is the result of cancer.
Cancer can take many forms; however, the generic term is used for a large group of diseases that can affect any part of the body. One defining feature of cancer is the rapid creation of abnormal cells that grow beyond their usual boundaries. Additionally, these cells can invade adjoining parts of the body and spread to other organs – which is the major cause of death from cancer.
Cancer arises from the transformation of normal cells into tumorous cells in a multistage process that generally progresses from a pre-cancerous lesion to a malignant tumour.
Globally, the most common cancers are:
- Lung (1.69 million deaths)
Lung cancer is the leading cause of cancer death in the world and it also has the lowest survival rate of any form of cancer.
According to the experts at House Call Doctor, lung cancer occurs when abnormal cells in one or both lungs grow in an uncontrolled way. The lungs are part of the body’s respiratory system and are made up of a series of airways called bronchi and bronchioles that end in tiny air sacs called alveoli. Lung cancer can form in all of these areas.
There are two main types of lung cancer, which are named for the size of the cancerous cells seen under a microscope: small cell lung cancer and non-small cell lung cancer. Around 85 to 90 per cent of lung cancers are non-small cell cancers.
- Liver (788 000 deaths)
The liver plays a pivotal role in removing toxic waste from the body and is located in the upper right-hand side of the abdomen, inside the rib cage. Liver cancer is seen more often in men than in women.
There are two main types of liver cancer, named after the part of the liver in which the cancer first develops.
- The most common type of liver cancer starts in the main cells of the liver. This is called hepatocellular carcinoma
- Cholangiocarcinoma begins in cells that line the bile duct.
- Colorectal (774 000 deaths)
Also known as bowel cancer, colorectal cancer occurs in the colon or rectum. If detected early, the chance of successful treatment and long-term survival improves significantly.
Early screening for colorectal cancer and preventative measures are crucial since there are often no symptoms until the cancerous cells have multiplied and spread to other organs.
Most bowel cancers are thought to develop from non-malignant growths on the lining of the wall of the bowel. These non-malignant growths are called adenomas or polyps.
Everyone is at risk of developing bowel cancer, however the risk greatly increases with age, particularly from the age of 50.
Risk factors for cancers
Common risk factors associated with various types of cancer include:
- Tobacco use
- Unhealthy diet
- Physical inactivity
- Family history.