Gastrointestinal Cancer –
Gastrointestinal cancer refers to malignant conditions of the gastrointestinal tract (GI tract) and accessory organs of digestion, including the esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum, and anus.
The symptoms relate to the organ affected and can include obstruction (leading to difficulty swallowing or defecating), abnormal bleeding or other associated problems. The diagnosis often requires endoscopy, followed by biopsy of suspicious tissue. The treatment depends on the location of the tumor, as well as the type of cancer cell and whether it has invaded other tissues or spread elsewhere. These factors also determine the prognosis.
Treatment commonly includes surgery, chemotherapy and radiation therapy.
TYPES OF GI CANCER
BOWEL, SMALL INTESTINE, AND ANAL CANCERS
Bowel cancer is sometimes known as colorectal cancer. The bowel is part of the body’s digestive system, which connects the stomach to the anus. Together the large colon (large intestine) and rectum are known as the bowel. Bowel cancer is a diseased growth that usually develops inside the large bowel. Most bowel cancers develop from small growths inside the colon or rectum called polyps, which look like small spots on the bowel lining or like cherries on stalks.
Not all polyps become cancerous. A test called a colonoscopy, involving a tube inserted into the bowel, is used to test for polyps. If polyps are detected and removed, the risk of bowel cancer is reduced.
STOMACH CANCER, GIST, AND NETS
Most stomach cancers develop in cells that line the mucosa and are called adenocarcinoma of the stomach. Stomach cancer (also known as gastric cancer) develops slowly – it may take many years before any symptoms are felt.
Just over 2,000 people are diagnosed with stomach cancer each year. This figure includes a small number of people diagnosed with gastrointestinal stromal tumors (GIST) or neuroendocrine tumors (NETs) – relatively rare cancers that are found mostly in the stomach but can occur elsewhere in the digestive system. Their symptoms and progress vary widely.
The liver is a key organ in the body. It produces bile, which breaks down the fats in food so that they can be absorbed from the bowel. The liver helps process fats and proteins, some of which are essential for blood clotting. The liver stores glycogen which is made from sugars to fuel the body. It also helps to process alcohol, some medicines, toxins, and poisons to remove them from the body.
In addition to these people, there are those who have secondary liver cancers – originating from cancers from other organs such as the colon or rectum spreading (metastasizing) to the liver. This will occur in about 40% of people suffering from bowel cancer.
The esophagus is the food pipe that carries food from your mouth to your stomach. The esophagus has three main sections – the upper, middle and lower. Cancer can develop anywhere along the length of the esophagus.
Glands in the wall of the oesophagus produce mucus to help food slide down more easily when swallowing. These glands can become cancerous to produce adenocarcinoma of the oesophagus, which is the most common type of cancer seen in Western countries (the other most common type is squamous cell carcinoma).
The pancreas is a thin, lumpy gland that lies between the stomach and spine. It is about 13 cm long and is joined by a special duct (the pancreatic duct) to the first part of the small bowel (called duodenum). The pancreas plays two major roles in the body: to produce insulin, which controls the amount of sugar in the blood; and to produce enzymes, which help in food digestion.
Pancreatic cancer begins in the lining of the pancreatic duct. It spreads into the body of the pancreas before moving into the blood vessels and nerves around the pancreas, obstructing the bile duct. Cancer that develops in the pancreas may also spread via the blood or the lymphatic system to other parts of the body.