Gastrointestinal Cancer

As there are multiple organs that make up the digestive system, gastrointestinal cancers are a broad category for the cancers that can arise in any of these organs. They arise as a result of uncontrolled growth and proliferation of the cells that are found in any of these organs.

The types of cancers that arise in the digestive system are categorised based on the organ and the cell type from where it begins.

Oesophageal cancer

Cancers in the oesophagus usually begin in the cells lining the inside of it. The cancer can then spread outwards through the other layers. The cells of the mucosal membrane (the layer that lines the inside of the oesophagus) include squamous (thin and flat) cells and glandular (secretory function, producing and releasing fluids such as mucus) cells. The two most common forms of oesophageal cancers begin in these cells.

• Squamous cell carcinoma – cancer that develops in these cells are usually found in the upper and middle part of the oesophagus
• Adenocarcinoma – cancers of the glandular cells, usually start in the lower part of the oesophagus

Stomach (gastric) cancer

Stomach cancers may present as pre-cancerous changes before the true cancer develops. It may take many years for the cancer to develop. The difficulty is that the early pre-cancerous changes rarely cause symptoms and may be hard to detect. Some of the types of cancers that can develop in the stomach are:

• Adenocarcinomas – make up about 90-95% of stomach cancers. These cancers develop from the innermost lining of the stomach
• Lymphoma – cancers of the immune cells, but can be found in the wall of the stomach. For more information about lymphomas, please click here.
• Gastrointestinal stromal tumour – these rare tumours develop from the interstitial cells of Cajal, which are located in the muscle layer of hollow GIT organs. These tumours can be found anywhere in the GIT from the oesophagus to the anus, but are most commonly found in the stomach.
• Carcinoid tumour – tumours that develop from endocrine (hormone-making) cells of the stomach.
• Lymphoma – cancer of the immune cells in the wall of the stomach.

Small intestine cancer

There are 3 sections of the small intestine – the duodenum, jejunum and ileum. Most cancers of the small intestine begin in the duodenum, especially in a specific area called the ampulla of Vater. The small intestine is made up of many different cell types, therefore different types of cancer may arise.

• Adenocarcinomas – accounting for 1 in 3 small intestine cancers
• Carcinoid tumours – tumours of endocrine cells. These tend to be slow-growing, and are the most common type of small intestine tumour.
• Lymphomas – cancers of the immune cells in the wall of the small intestine. For more information about lymphomas, please click here.
• Sarcomas – cancers that start in the muscle and other connective tissue in the intestinal wall

Gallbladder cancer

Gallbladder cancers are rare. Nearly all of them are adenocarcinomas – cancer that arises in the glandular cells. One subtype of adenocarcinoma is papillary adenocarcinoma. It is called papillary because of the arrangement of cells that resemble finger-like projections. This type of cancer has a better prognosis than other types of adenocarcinomas.

Pancreatic cancer

Glands of the pancreas that produce pancreatic enzymes (for digestion) or other products are called exocrine glands. Cancers of the exocrine glands are the most common type of pancreatic cancer.

• • Adenocarcinomas – make up 95% of exocrine cancers
    • Ductal adenocarcinomas – begin in the ducts of the pancreas
    • Acinar adenocarcinomas – begin in the cells that make pancreatic enzymes
  • Neuroendocrine tumours – uncommon in comparison to exocrine cancers. Begin in the cells that make hormones that control our body’s blood sugar levels
  • Ampullary cancer – starts at the ampulla of Vater, where the bile duct and pancreatic duct join to empty bile and pancreatic enzymes into the small intestine

These above lists contain just a few examples of the different cancers that can develop in the organs of the digestive system (see also: liver and colorectal cancers). The different types of cancer have different prognoses and outlooks, as well as treatment plans.

Unexplained weight loss may present as one of the symptoms of cancers in the oesophagus, stomach, small intestine, gallbladder or pancreas. Nausea, accompanied with or without vomiting, is another symptom of all these cancers.

The lists below include a comprehensive list of other symptoms that may present each category of cancer.

Oesophageal cancer

• Difficulty or pain when swallowing
• Chest pain, or a pressure or burning sensation in the chest
• Indigestion
• Heartburn
• Coughing or hoarseness

Stomach cancer

• Upper abdominal pain
• Persistent indigestion
• Loss of appetite
• Heartburn
• Black stools
• Anaemia

Small intestine cancer

• Abdominal pain that is crampy and worsens after eating
• Weakness and fatigue
• Black stools
• Anaemia

Gallbladder cancer

• Abdominal pain at the upper right part of the belly
• Jaundice – yellowing of the skin and eyes
• Lumps in the belly
• Fever
• Itchy skin
• Dark urine
• Light-coloured or greasy stools

Pancreatic cancer

• Jaundice – yellowing of the skin and eyes
• Dark urine
• Light-coloured or greasy stools
• Itchy skin
• Abdominal or back pain
• Gallbladder or liver enlargement
• Blood clots
• Diabetes

These symptoms may also present in other less serious conditions. If you are experiencing any of these symptoms, it is important that you bring this to your doctor’s attention. Some cancers may present with non-specific or few symptoms that are easily missed, and as a result, they may go undetected. Your doctor will be able to help you find the cause of the symptoms you are experiencing.

Having a blood relative (family history) who has had any of these gastrointestinal cancers is a risk factor for an individual to develop the cancer as well. Below is a list of risk factors of the different cancers, specific to the organ they may begin in.

Oesophageal cancer

• Heavy drinkers
• Habitual smokers
• Individuals suffering from gastrooesophageal reflux disease (GERD)
• Individuals with Barrett’s oesophageous
• Obese patients (more likely to have acid reflux)
• Achalasia (condition where muscles of the oesophagus are unable to relax)

Stomach cancer

• History of Helicobacter pylori infection
• Having a stomach lymphoma in the past
• Having a stomach polyp in the past
• Chronic gastritis (long term stomach inflammation)
• Having a diet high in salty and smoked foods
• Having a diet low in fibre from fruits and vegetables
• Smoking

Small intestine cancer

• Men are more likely to develop small intestine cancer
• Older age
• Individuals of African descent
• Smoking and alcohol use
• Having a diet high in salty and smoked foods
• Having Celiac disease
• Having a history of colon cancer
• Individuals with cystic fibrosis
• Having certain inherited syndromes such as:
  • Famililal adenomatous polyposis (FAP)
  • Peutz-Jeghers syndrome (PJS)
  • Lynch syndrome
  • MUTYH-associated polyposis
• Individuals with Crohn’s disease

Gallbladder cancer

• Having gallstones
• Chronic inflammation of the gallbladder due to gallstones
• Females are more likely to develop gallbladder cancer
• Obesity
• Older age
• Individuals of Mexican, Latin and Native American descent
• Having a cyst in the common bile duct
• Individuals with abnormal bile ducts
• Having a history of gallbladder polyps

Pancreatic cancer

• Older age (above 45)
• Men are more likely to develop pancreatic cancer
• Individuals of African descent
• Having certain inherited syndromes such as:
  • Hereditary breast and ovarian cancer syndrome
  • Hereditary breast cancer
  • Familial pancreatitis
  • Lynch syndrome
  • Peutz-Jeghers syndrome
• Smoking and alcohol use
• Obesity
• Diabetes
• Chronic inflammation of the pancrease
• Exposure to chemicals used in dry cleaning or metal working industries

Anyone who has an increased risk of developing gastrointestinal cancer should consult and let their doctor know about the specific risk factors they may have. Your doctor will then be able to plan the necessary measures to monitor your health, so that in the case that the cancer does develop, it may hopefully be detected earlier where it will be more treatable.

Your doctor will want to know your personal and family medical history, and he/she will conduct a physical examination of your abdomen. If your doctor suspects you may have gastrointestinal cancer, there are several tests he/she may conduct in order to reach a diagnosis.

For some of the gastrointestinal cancers, there may be blood tests to look for certain tumour markers. These chemical levels may be altered in your blood, and if so, may be an indicator for an underlying cancer. However, cancer cannot be diagnosed by a blood test alone.

Your doctor may recommend for you to undergo an endoscopy. This involves the use of a camera attached to a long, flexible tube to examine the inside of the oesophagus, stomach and small intestine. If there are any abnormalities, your doctor may conduct a biopsy. This is the removal of a small sample of tissue to be examined under the microscope.

The use of imaging may also help your doctor to detect any abnormalities or find the location of the tumour. Imaging modalities that are commonly used by doctors to find gastrointestinal cancers include barium swallow X-rays, magnetic resonance imaging (MRI), computed tomography (CT scans), and ultrasound scans.

The tests used to diagnose gastrointestinal cancer depends on the location and type of cancer. It is important to consult your doctor to understand what he/she may plan to use in order to rule out or diagnose cancer.

Treatment options for gastrointestinal cancers depends on the location and stage of the cancer, as well as the patient’s age and overall health.

There are a variety of treatment options available, and is personalised to each patient. Sometimes, different options may be used in combination as well. The options include:

• Surgery
• Chemotherapy
• Radiation therapy
• Targeted drug therapy
• Immunotherapy

Once the diagnosis is made, a consultation with an oncologist is essential in order to understand which treatment options are the most suitable.