Lower Gastrointestinal Tract Cancer

The lower gastrointestinal tract, commonly referred to as the large intestine, begins at the cecum and also includes the appendix (humans only) colon, rectum, and anus. The primary function of the large intestine in all three species is to dehydrate and store fecal material. Lower gastrointestinal (or lower GI) cancer refers to cancers of the large bowel (colon and rectum) and the anus. 

Signs & symptoms of Lower GI cancer:

• A persistent change in one’s bowel habits, including diarrhea or constipation or a change in the consistency of the stool
• Rectal bleeding or blood in the stool
• Persistent abdominal discomfort, such as cramps, gas or pain
• A feeling that the bowel doesn't empty completely
• Weakness or fatigue
• Unexplained weight loss

The lower GI tract runs from the small intestine to the large intestine (colon) to the anus.

Upper GI bleed is more common than lower GI bleed. Upper GIT bleeding is from the esophagus, stomach, and duodenum proximal to the ligament of Treitz. Lower GIT bleeding is distal to the ligament of Treitz and colon.

Gastrointestinal (GI) cancer is a term used for the group of cancers that affect the gastrointestinal tract and other organs that are present within the digestive system, including the esophagus, pancreas, stomach, colon, rectum, anus, liver, biliary system, and small intestine.

Generally, colorectal cancer may never go away completely. Some people may get regular treatment with chemotherapy, radiation therapy, or other treatments to try to control the cancer for as long as possible. Learning to live with cancer that does not go away can be difficult and very stressful.

The development of a bowel cancer from a polyp may take between five and ten years. So,  one can assume that cancer in the colon can go undetected for up to 10 years, meaning, a colonoscopy turns up normal results, and then one a decade later shows a malignant tumor. 

• Adenocarcinomas, which account for over 95% of colon and rectal cancers. These cancers originate in the colon or rectum's mucus cells.
• Lymphoma, a cancer of the immune system. While these most commonly start in your lymph nodes, they also sometimes occur in the colon or the rectum.
• Sarcomas, which start in the rectum or colon's blood vessels or muscle tissues.
• Carcinoid tumors, which originate in the colon and rectum's hormone-producing cells.
• Gastrointestinal stromal tumors, which can be found anywhere in the gastrointestinal system.

Different treatments required such as:

• Surgery and radiation therapy are mainly used to treat only the cancer. They do not affect the rest of the body. 
• Drugs such as chemotherapy, targeted therapy and immunotherapy go through the whole body. They can reach cancer cells almost anywhere in the body.