Collectively, GI cancers are the most common type of cancer in New Zealand with nearly 5,000 new cases diagnosed each year. GI cancer affects male and females equally. More than half of those diagnosed with GI cancer die within five years of their diagnosis. Bowel cancer is the most common GI cancer, and New Zealand has one of the highest bowel cancer death rates from in the world. Each year, GI cancers kill more New Zealanders than prostate and breast cancers combined, and they remain underrepresented in public consciousness.
The oesophagus, or ‘food pipe’, carries food from the mouth to the stomach. It is about 26 cm long in adults and passes through the chest, behind the windpipe and the heart. The oesophagus has three main sections – the upper, middle and lower. It carries food and liquids to the stomach using waves of muscle contractions. The wall of the oesophagus has several layers (the mucosa, sub mucosa and muscularis) that help to push food down towards the stomach. Glands in the wall produce mucus to help food slide down more easily when swallowing. The oesophagus joins to the top part of the stomach (called the cardia) where a valve (the gastro-oesophageal sphincter) keeps the stomach contents from coming back up into the oesophagus. Cancer can develop anywhere along the length of the oesophagus but it most commonly arises in the lower third, towards the stomach end. There are two main types of oesohageal cancer, called squamous cell and adenocarcinoma. The risk factors for developing oesophagus cancer include a condition called Barrett’s oesophagus, excessive alcohol consumption, and smoking. However, oesphagus cancer can arise when none of these risk factors are present. The symptoms of oesophagus cancer include difficulty swallowing and weight loss. It is important to realize that these symptoms can also occur in other non-cancerous conditions. Oesophagus cancer is usually diagnosed by endoscopy, where a flexible tube with a camera on the end is passed down from the mouth, and samples of tissue, called biopsies, are taken and sent to the lab for testing. Other tests used include barium x-rays and CT scans. The treatment of oesophagus cancer depends on its site within the oesophagus, the stage of the cancer (how advanced it is at the time of diagnosis), and whether the person is otherwise medically fit. Treatment options include surgery, radiotherapy, and chemotherapy. These treatments are sometimes used in combination. The prognosis after treatment depends on the stage and the treatment given. In the best circumstances, cure is possible. If cure is not possible, the symptoms caused by the cancer can often be alleviated.
The stomach is a muscular sack-like organ that receives and stores food from the oesophagus. With the help of gastric juices that are released from glands in the inner lining of the stomach, the stomach breaks down food into a thick liquid. Once the food is broken down, it is passed from the stomach to the small bowel, where nutrients are absorbed into the bloodstream.
There are several different types of stomach cancer:
- Adenocarcinomas: about 90% of stomach cancers develop in the cells that line the inside surface of the stomach and are called gastric adenocarcinomas.
- Lymphomas: cancer of specialised cells that are part of the immune system. These can arise in the stomach or other parts of the digestive tract.
- Gastro-Intestinal Stromal Tumours (GISTs): cancer arising from pacemaker cells that control stomach wall muscle contractions. GISTs can also develop in other parts of the digestive tract but most frequently occur in the stomach.
- Carcinoid tumours (also known as neuroendocrine tumours or NETs): cancer of hormone-producing cells. These can arise in the stomach as well as in other parts of the digestive tract.
The symptoms of stomach cancer are often vague and non-specific but may include: indigestion, early fullness after eating, loss of appetite, unexplained weight loss, blood loss, and pain. Some of these symptoms are often subtle and occur in other medical conditions apart from stomach cancer, making them difficult to link to stomach cancer.
Stomach cancer is usually diagnosed by endoscopy, where a flexible tube with a camera on the end is passed down from the mouth, and samples of tissue, called biopsies, are taken and sent to the lab for testing. Other tests used to help with the diagnosis include barium x-rays and CT scans.
The treatment of stomach cancer depends on its site within the stomach, the stage of the cancer (how advanced it is at the time of diagnosis), the type of cancer, and whether the person is otherwise medically fit. Surgery to remove part or all of the stomach is the most common treatment, but radiotherapy and chemotherapy may also be used. These treatments are sometimes used in combination.
The prognosis after treatment depends on the stage and the treatment given. In the best circumstances, cure is possible. If cure is not possible, the symptoms caused by the cancer can often be alleviated.
The liver is one of the largest organs in the body and is situated in the upper abdomen under the ribcage. The liver has a number of functions that make it essential to life. These include:
- Regulating sugars and fats so they can be used for energy Storing glucose and vitamins so that they can be released into the bloodstream when needed
- Producing proteins which are essential for blood clotting and prevent excessive bleeding while other proteins help regulate fluid levels in the body
- Producing bile which is released into the intestine to break down the fats in food so they can be absorbed in the bowel
- Processing substances including alcohol, drugs and by-products of normal metabolism so they can be passed out of the body or broken down into harmless substances
The gall bladder is connected to the bile ducts. It is a small pouch that stores and concentrates the bile that is made by the liver. Bile from the liver passes down the bile ducts into the small intestine where it aids with the digestion of fats. The gall bladder and bile ducts are known as the biliary tract.
The gallbladder is lined by the same type of cells that line the bile ducts, and gallbladder cancer is therefore similar to bile duct cancer, which is also known as cholangiocarcinoma. These cancers are most common in patients over the age of 60. Gallbladder cancer usually occurs in people who have gallstones. Chronic inflammation of the bile ducts (primary sclerosing cholangitis) predisposes a person to bile duct cancer, but it can also occur in the absence of this condition.
Bile duct cancers often cause jaundice (a yellowing of the skin and eyes) due to obstruction to the flow of bile out of the liver. Gallbladder cancer does not usually cause symptoms until it becomes more advanced. However, it may be discovered at an earlier stage due to pain from the gallstones. Gallbladder cancer is sometimes diagnosed unexpectedly when the gallbladder has been removed to treat gallstones. It’s important to note that gallstones are a very common condition and that the majority of people with gallstones do not develop gallbladder cancer.
Radiology tests, such as a CT scan or an MRI, are done to help diagnose and stage the cancer and determine the best treatment options.
The main treatment for gall bladder and bile duct cancer is surgery. This is only suitable if the cancer has not spread. Other treatments such as chemotherapy and radiotherapy may be used, and blockages of the bile duct can usually be alleviated with stents (a plastic or metal tube inserted through the blocked section).
The prognosis depends on the stage and whether or not it is possible to remove the cancer with surgery. In the best circumstances, cure is possible. If cure is not possible, the symptoms caused by the cancer can often be alleviated.
The pancreas is a narrow gland that lies deep in the abdomen between the stomach and the spine. It is about 15cm long and is made up of three parts, the head, body and tail. The head lies next to the first part of the small intestine (duodenum) and the lower end of the bile duct. The pancreas has two key functions as part of the digestive system; it produces the hormone insulin that controls the level of sugar in the body, and produces pancreatic enzymes that aid in the chemical breakdown of food so nutrients can be absorbed in the intestine. These enzymes flow down a tube (the pancreatic duct) into the small intestine. More than 90% of pancreatic cancers start from the cells in the inner lining of the pancreatic ducts. These are called adenocarcinomas. The most common site is in the head of the pancreas. The other types of pancreatic cancer are much less common and include:
- Pancreatic neuroendocrine tumours (NETs) are a group of tumours that produce hormones. For more information on NETs, visit the Unicorn Foundation
- Lymphoma is cancer of specialised cells that are part of the immune system, it can occur in the pancreas and in other parts of the digestive tract.
- Mucin producing tumours that grow along the pancreatic ducts and cause obstruction (intraduct papillary mucinous neoplasm). These tumours can be benign or malignant.
The bowel connects the stomach to the anus, and is divided into two parts: the small bowel (also known as the small intestine) and the large bowel (or the large intestine). The small bowel is 3-5 metres in length, and is where most of the nutrients from the diet are absorbed. The large bowel is about 1 metre in length and is made up of the colon and the rectum. The function of the colon is to finish absorbing water and electrolytes. The bowel contents are then stored in the rectum until being passed out as faeces. Bowel cancer, also called colorectal cancer, is the most common type of GI cancer. New Zealand has one of the highest rates of bowel cancer in the world, with approximately 3,000 new cases each year. Nearly all bowel cancers arise in the large bowel, and small bowel cancer is rare. Most bowel cancers develop from small benign growths, called polyps, on the inside lining of the bowel. Not all polyps become cancerous, and the risk of developing cancer in a polyp depends on the type of polyp and its size. A colonoscopy, a procedure in which a flexible tube with a camera is passed through the anus and around the bowel, can detect and remove polyps to reduce the risk of developing bowel cancer. About 5% of bowel cancers occur as a result of changes in genes that are passed on from one generation to the next (familial bowel cancer). Familial bowel cancer can be diagnosed by special tests to detect these gene changes, and is more common in young patients and those with a strong family history of cancer. Special counselling is available for people with a diagnosis of familial bowel cancer. The symptoms of bowel cancer include a change in bowel habit (constipation, diarrhoea or noticeable change in the regularity of bowel movements), bleeding from the bowel, abdominal pain, bloating, and unexplained anaemia (on a blood test). It is important to note that these symptoms can also be associated with other conditions that are not related to bowel cancer. Bowel cancer is usually diagnosed by colonoscopy. Biopsies can be taken and polyps can also be removed during colonoscopies. Radiology tests can be used to diagnose bowel cancer, including barium enema and a special type of CT scan called CT colonography. Surgery to remove the affected part of the bowel is the main treatment for bowel cancer. Additional treatment with chemotherapy is sometimes required, depending on the stage of the cancer. Radiotherapy is sometimes used in addition to surgery and chemotherapy to treat rectal cancer. The prognosis of bowel cancer depends on the stage. The stage is determined by scans and by examination of the bowel removed at surgery. Patients with stage 1 and 2 bowel cancer have a good chance of being cured with surgery alone. At least half of stage 3 patients can be cured with a combination of surgery and chemotherapy. The prognosis for stage 4 bowel cancer depends on the circumstances. In the best circumstances cure may still be possible.
- Stage 1 cancer: Stage 1 means the cancer is confined to the lining of the bowel and there is no sign of spreading elsewhere. These cancers are treated with surgery alone and there is a high chance of cure.
- Stage 2 cancer: Stage 2 means the cancer has penetrated into the deeper layers of the bowel wall, but has not spread to the lymph glands or elsewhere. Stage 2 cancer is usually treated by surgery alone, but chemotherapy may be advised in particular circumstances to reduce the risk of the cancer coming back. These circumstances include bowel blockage or bowel perforation, or particular features of the tumour that the pathologist looks for under the microscope.
- Stage 3 cancer: Stage 3 means that cancer cells have been detected in the lymph glands that were removed with the bowel at the time of surgery. Stage 3 bowel cancer has a higher chance of coming back, and chemotherapy can reduce the risk of the cancer returning. Stage 3 bowel cancer is therefore treated with surgery followed by chemotherapy. The treatment of rectal cancer differs in some ways from the treatment of colon cancer. Radiotherapy is often used prior to surgery in rectal cancer to reduce the risk of the cancer coming back in the pelvis. The radiotherapy is usually given, in combination with chemotherapy, prior to surgery. Because the rectum is the very lowest part of the bowel, some patients with rectal cancer will also need a stoma (bag). This is usually temporary, but sometimes it is permanent.
- Stage 4 cancer: Stage 4 means the cancer has spread to other organs or tissues. It can spread inside the abdomen or to other parts of the body. This type of spread is called metastasis or secondary spread. The liver is the most common organ affected. Stage 4 disease can sometimes be cured by surgery, usually in combination with chemotherapy. However, it is often not possible to cure stage 4 colon cancer. If this is the case, treatment may be able to control the cancer for some time. Treatment may also reduce symptoms and help provide a better quality of life.