Digestive system cancer includes tumors in the esophagus, stomach, liver, pancreas, gallbladder, and colon, which can affect the rectum or anus. Each type of gastrointestinal cancer develops from cells found in the specific organ. Some forms of digestive system cancer do not produce symptoms until the disease progresses, but screening can identify tumors at an early stage.
Pancreatic cancer is considered difficult to diagnose and treat because this type of cancer of the digestive system rarely develops early signs. Two types of cells in the pancreas can become cancerous: endocrine cells or exocrine cells. Endocrine cells make hormones that the body uses for many different functions. Also called islet cells, tumors in these cells rarely become cancerous.
Exocrine cells produce the enzymes needed to digest food. They exist in the sacs where 95 percent of all pancreatic cancers start. Malignant tumors can cause stomach or back pain, diarrhea, or heartburn as the cancer spreads within the pancreas or nearby organs. In some patients, the skin and the whites of the eyes take on a yellowish tint. The prognosis for cancer of the digestive system that affects the pancreas depends on the stage of the disease, whether it has spread, and the type of abnormal cells.
Primary or secondary liver cancer can develop within the liver or elsewhere before spreading to the liver. The liver is located inside the rib cage and serves as a filter for harmful substances. It sends toxic material into the urine and feces for excretion and produces bile to digest food. Liver tumors usually progress rapidly to an advanced stage and occur more often in people with cirrhosis or hepatitis.
Stomach cancer usually begins in the cells of the inner lining of the stomach before spreading to other layers. Acids in the stomach break down carbohydrates, fats, proteins, vitamins, and minerals for use. Advanced stomach cancer can make swallowing difficult, cause pain, or appear as bloody stools. Indigestion, nausea, and loss of appetite represent other symptoms of the disease. The risks of stomach cancer increase with age, poor diet, and other stomach conditions, such as bacterial infection, inflammation, and ulcers.
Colon cancer can develop in the large or small intestine and represents the most common form of cancer of the digestive system. It could be cured if caught early by surgically removing the tumors or a section of the colon where there are cancer cells. Any change in bowel habits, such as constipation, diarrhea, smaller stools, or bloody stools, can indicate colon cancer. People over the age of 50 and patients with a family history of colon cancer face higher risks of the disease.