GI Cancers or Gastrointestinal cancers is a term used to refer to the group of cancers that affect the gastrointestinal tract of the body and other organs of the digestive system such as oesophagus, pancreas, stomach, colon, rectum, anus, liver, biliary system and the small intestine. GI cancers can affect both men and women. These cancers mostly develop within the wall of the stomach or the small intestine and grow in the empty space of gastrointestinal tract (GI); hence, they might not cause any symptoms or signs till they spread or start affecting a particular organ or reach a certain size.
Small gastrointestinal tumours might not cause any symptoms and could be diagnosed by the doctor during a test or while examining for some other issue. That said, GI cancers are widespread and are responsible for the maximum number of deaths caused by cancer, globally. Thus, it is critical to know about gastrointestinal cancer, its types, symptoms and treatment options.
Types of Gastrointestinal Cancers and Surgeries
All types of cancers affecting the gastrointestinal tract and other digestive organs are classified as gastrointestinal cancers. The most common types of gastrointestinal cancers include:
Anal Cancer: Anal cancer is a form of gastrointestinal cancer which affects the anal canal in the body. Anal canal located at the end of the rectum is a small tube through which the body excretes stool. Anal cancers develop in the inner lining of the anal canal known as mucosa; when cancer develops from cells in the glands under the mucosa – the type of cancer is called adenocarcinomas. That said, the anus canal can also host other tumours which can be non-cancerous. Hence, a medical examination can only confirm the presence of anal cancer.
Once confirmed, the first option for treatment includes a combination of chemotherapy and radiation, when both forms of treatment do not work, the doctors will recommend surgery to remove anal cancer depending on the stage of cancer. For benign tumours, the doctors will surgically remove the tumour, as well as some healthy tissue surrounding it. For more advanced tumours, an extensive surgery called abdominoperineal resection may be performed in which the anal canal, rectum and a part of the colon are removed, and the remaining part is attached to an opening in the abdomen for excretion of waste.
Colon and Rectal Cancer (Colorectal Cancer): Colorectal cancers are initially small and non-cancerous formations of cells, called polyps that tend to develop in the inner lining of the colon or the rectum. When these polyps advance and become denser, the cells convert to cancerous leading to colorectal cancer which can either start from the colon or the rectum. It is advised to get regular medical examinations done for the colon and rectal to avoid build-up of polyps because they are the breeding grounds for colorectal cancer and usually do not produce any symptoms.
Various forms of surgery can be used to treat colorectal cancer depending on the severity of the condition. A polypectomy can be conducted by inserting a special instrument into the rectum to assess and remove polyps. In another surgery called local excision, the rectum cancer and some tissue of the rectum wall may be removed through the anus or a small incision in the rectum. The rectum is another surgical treatment that involves removing the part or the entire colon, along with cancer. In addition, laparoscopic surgery can also be used to treat colorectal cancer.
Oesophagal Cancer: A form of gastrointestinal cancer which affects the oesophagus is known as oesophagal cancer. The oesophagus is a hollow, muscular tube which connects the throat (pharynx) with the stomach. It usually is about 8 inches long and is surrounded by moist pink tissue known as mucosa. The oesophagus is located behind the trachea and the heart, in front of the spine. This tube is responsible for moving the food to the stomach for digestion. The tube has three sections – upper, middle and lower – and cancer can affect anywhere along the length of the tube.
Surgery is the main form of treatment for patients who have oesophagal cancer. The type of surgery called an esophagectomy involves removing a part of the oesophagus and connecting the remaining part of the oesophagus, which is not affected with cancer, to the stomach to support swallowing of food; this connection may be done by placing a plastic tube or using a part of the intestine. Moreover, if the oesophagus is partly blocked by cancer, a stent may be placed to keep it open.
Gallbladder and Biliary Tract Cancer: A gallbladder is a small pouch in the form of a pear, which is located right under the liver and is responsible for storing bile produced by the liver. Bile aids digestion and helps in the absorption of fat in the small intestine. In gallbladder cancer, malignant cancer cells develop in the tissues of the gallbladder; while in biliary tract cancer or cholangiocarcinoma, cancer cells affect the bile ducts – drainage tubes that carry bile from the liver to the gallbladder and then from the gallbladder to the small intestines. Biliary tract cancer can develop anywhere along the bile duct length. The most common form to treat a gallbladder cancer is a cholecystectomy in which the gallbladder and surrounding lymph nodes are removed through a surgical procedure.
Liver Cancer: Cancer that starts in the cells of the liver is referred to as liver cancer. The liver is the largest organ of the human body and is located on the right side of the abdomen below the diaphragm and above the stomach. This meaty organ is responsible for detoxifying metabolites, synthesizing proteins, and producing biochemicals required for digestion of food in the body. Liver cancer is particular cancer that specifically develops in the liver cells; however, various other cancers can affect the liver but are not called liver cancers. Liver cancer can be of more than one type, the most common is hepatocellular carcinoma, which affects hepatocyte – the main liver cells.
Two types of surgical procedures are used to treat liver cancer, primarily hepatocyte. These include:
- Hepatectomy: In this procedure, the affected part of the liver is removed and the other healthy part of the liver takes over the functioning of the whole liver and grows back to its normal size within a few weeks.
- Liver Transplantation: When the size of the tumour is too big, and the condition of the patient has worsened, the doctors might consider liver transplantation to remove cancer from the body. The patient should, however, meet some defined criteria and there should be a healthy liver available for transplantation.
Pancreatic Cancer: A type of cancer that starts in the cells of the pancreas (exocrine and endocrine) is called Pancreatic Cancer. Pancreas are located behind the stomach and are responsible for releasing enzymes which help in digestion of food and also produce hormones that control the blood glucose level. Pancreatic cancer is one of the most dangerous forms of cancer because it is very hard to diagnose, which delays the treatment until it has reached advanced stages of cancer.
Surgery to treat pancreatic cancer is of the following types:
- Whipple Procedure: In this, the head of the pancreas, as well as the first part of the small intestine, gallbladder and bile duct, are removed. Then the end of the bile ducts and the healthy part of the pancreas are attached to the small intestine.
- Distal Pancreatectomy: In this surgical procedure, the tail and the body of the pancreas are removed. This might also involve removing the spleen, part of the stomach, bowel, left adrenal gland, left kidney and left diaphragm.
- Total Pancreatectomy: In this procedure, the entire pancreas will be removed. This can have a lot of after-effects which should be carefully discussed.
Stomach Cancer: Stomach cancer, also known as gastric cancer or gastric adenocarcinomas, is a formation of abnormal cells that create a mass in the stomach. Though the mass can develop in any part of the stomach, it most commonly starts in the mucus-producing cells of the inner lining of the stomach.
Surgeries to treat stomach cancer can include either a partial gastrectomy or a total gastrectomy; in the former, a part of the stomach and the surrounding lymph nodes and fatty tissues are removed to eradicate cancer. However, in the latter, the entire stomach, as well as lymph nodes and fatty tissues are removed, and a new stomach is formed by folding over a part of the intestines.
Small Intestine Cancers: Small intestine cancers or small bowel cancers are the type of gastrointestinal cancers which affect the small intestines – organs in the GI tract that are responsible for absorption of nutrients and minerals from the food. The small intestines are located between the stomach and the large intestines and receive bile and pancreatic juice from the pancreatic duct, to help digestion of food. The small intestines are formed of a variety of cells and hence, different types of cancers can develop in them. Four of the major types of small intestinal cancers include:
- Carcinoid Tumours
There are two types of surgeries which can be used to treat small intestine cancers. These are – Resection in which a part or all of the small intestine is removed along with nearby organs that are affected with cancer. In other cases, bypass surgery may be performed in which the food from the small intestine is bypassed from the tumour blocking the movement.