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Gastrointestinal cancer refers to any primary cancer of the gastrointestinal tract and associated organs. Types of gastrointestinal cancer include esophageal cancer, stomach cancer, colorectal cancer and anal cancer. Malignancies also can develop in organs of the gastrointestinal system, such as the liver, gallbladder and pancreas. Another type of malignancy, called a gastrointestinal stromal tumor (GIST), can develop in the esophagus, stomach or small intestine.
The causes of gastrointestinal cancer are not well understood, because there are many contributing factors involved. Several risk factors are known to contribute to the development of one or more types of gastrointestinal malignancy. These include smoking, a diet high in saturated fats, cured or salted foods and excessive alcohol use. People who are heaver than a healthy weight also are thought to be more at risk of some gastrointestinal cancers. The risk of these types of cancer can be reduced by not smoking, maintaining a healthy weight and eating a balanced diet that is low in saturated fat and high in fiber and fresh foods.
Symptoms of gastrointestinal cancer are variable, because this cancer can affect several organs and different locations in the gastrointestinal system. The most common symptoms include nausea and vomiting, appetite loss, weight loss, tenderness or pain in the affected area, bloating and gas. Changes in bowel habits also can occur. These can include changes in the frequency of bowel movements and other changes such as constipation or diarrhea.
Another symptom that might develop as a result of gastrointestinal cancer is the presence of blood in stool. When bleeding is in the stomach or upper gastrointestinal tract, stools appear black and tarry. If, however, the bleeding is in the lower colon or rectum, the blood tends to be fresher and is more likely to retain its red color.
Cancer of gastrointestinal system organs, including liver cancer, gallbladder cancer and pancreatic cancer, can cause more specific symptoms in addition to those listed above. Gallbladder cancer causes pain in the upper right quadrant of the abdomen and can cause jaundice in addition to appetite loss and weight loss. Symptoms of pancreatic cancer can include upper abdominal and back pain, jaundice and high blood sugar. Liver cancer can cause jaundice and pain in the upper right abdominal quadrant.
Symptoms of gastrointestinal cancer are not always easily identifiable, because many of them, such as constipation, diarrhea and gastrointestinal problems, also are symptoms of other conditions. For this reason, any pain, changes in bowel habits and other gastrointestinal symptoms should be reported to a doctor if they persist longer than a week or two. Reporting symptoms early is important to ensure that diagnosis and treatment occurs as soon as possible. Diagnostic tests can include X-rays or other medical imaging tests, blood tests, biopsies and endoscopy.
Treatments for gastrointestinal cancers vary depending on the type of cancer involved and how far it has advanced. When a patient is a good candidate for surgery, treatment commonly involves surgical removal of cancer. This is followed by treatment with radiation therapy or chemotherapy to ensure that any remaining cancer cells are killed. The prognosis for gastrointestinal cancers is variable, depending on the type of cancer involved and whether it has spread to other parts of the body.