What is cancer and its types?

Cancer is no laughing matter for it is one of the deadliest diseases in the world. According to the World Health Organization (WHO), cancer is “…a generic term for a large group of diseases that can affect any part of the body.” It’s the leading cause of death worldwide with an estimated 8.2 million deaths in 2012. Cancer is caused by a single normal cell transforming into a tumor cell through several stages as a result of a person’s genetic factors interacting with external agents, such as physical carcinogens, chemical carcinogens, and biological carcinogens. As cancer can develop in any body organ, there are over 200 different types of cancer. Let’s take a quick look at the main types of cancer as identified by the WHO.

Lung cancer forms in the tissues of the lung, specifically in cells along the air passages. There are two main types of lung cancer: Small cell lung cancer and non-small cell lung cancer. Prolonged smoking is one major cause of lung cancer. Lung cancer accounts for 1.59 million deaths globally in 2012.

Liver cancer or hepatic cancer is formed in the tissues of the liver. It can also spread from the liver to other parts of the body. Primary cause of liver cancer is viral infection with either hepatitis C virus (HCV) or Hepatitis B virus (HBV). Liver cancer resulted to 745,000 deaths worldwide in 2012.

Stomach cancer, also known as gastric cancer, is formed in any part of the stomach. The main cause of stomach cancer is Helicobacter pylori infection. Smoking also increases the risk of getting stomach cancer. Stomach cancer claimed 723,000 lives in 2012 and 10,990 in the United States alone in 2014.

Colorectal cancer is also known as colon cancer, rectal cancer, bowel cancer, or colorectal adenocarcinoma. Colon cancer is formed in the tissues of the colon, which is the longest part of the large intestine. Rectal cancer is formed in the tissues of the rectum which is the last several inches of the large intestine that is closest to the anus. Risk factors attributed as the cause of colorectal cancer include old age, male gender, high fat intake, alcohol, red meat, obesity, smoking, and lack of physical exercise. In 2012, there were 694,000 deaths due to colorectal cancer.

Breast cancer is formed in the tissues of the breast, specifically in the inner lining of milk ducts or the lobules that supply milk to the ducts. The main risk factors for breast cancer include the female gender, older age, genetics, lack of childbearing, lack of breastfeeding, and higher levels of specific hormones. Breast cancer accounts for 521,000 deaths worldwide in 2012.

Oesophageal or esophageal cancer is formed in the tissues lining the esophagus which is the muscular tube where food passes from the throat to the stomach. Esophageal cancer is either squamous cell carcinoma or adenocarcinoma. Main causes of esophageal cancer include alcohol abuse, tobacco, and long-term sitting positions. There were 400,000 deaths due to esophageal cancer worldwide in 2012.