What is small bowel cancer?
Small bowel cancer (also called small intestine cancer) occurs when cells in the small bowel become abnormal and keep growing and form a mass or lump called a tumour.
The small bowel is a long tube that absorbs nutrients from food and carries food between your stomach and large bowel. The small bowel has three parts:
- duodenum – the first section, which receives broken-down food from the stomach
- jejunum – the middle section
- ileum – the final and longest section, which transfers waste matter to the large bowel.
The type of small bowel cancer is defined by the particular cells that are affected, and most commonly include:
- Adenocarcinoma – starts in epithelial cells that line the inside of the small bowel, often in the duodenum.
- Sarcoma – starts in connective tissue. Gastro-intestinal stromal tumours (GIST) start in nerve cells anywhere in the small bowel. Leiomyosarcoma starts in muscle tissues in the wall of the small bowel, often in the ileum.
- Neuroendocrine tumours (NETs) – form in neuroendocrine cells inside the small bowel, often in the ileum.
- Lymphoma – forms in lymph tissue in the small bowel, often in the jejunum. Non-Hodgkin lymphoma starts in lymphocytes, a type of white blood cell.
How common is small bowel cancer?
Small bowel cancer is rare. About 530 Australians are diagnosed each year (this is about 2 cases per 100,000 people). It is more likely to be diagnosed in men than women, and in people aged over 60 years.
Learn more about rare cancer
The cause of small bowel cancer is not known in most cases. However, there are several risk factors. Some small bowel cancers may be linked to Crohn’s disease and coeliac disease. Eating large amounts of animal fat and protein, especially processed meat and red meat, might also increase the risk.
Some rare, inherited diseases can put people more at risk of small bowel cancer. These include familial adenomatous polyposis (FAP), Lynch syndrome (hereditary nonpolyposis colorectal cancer, or HNPCC), Peutz–Jeghers syndrome (PJS) and cystic fibrosis (CF). Multiple endocrine neoplasia (MEN 1) may increase the risk of small bowel neuroendocrine tumours.
Small bowel cancer can be difficult to diagnose, and symptoms may be vague and caused by other conditions. Symptoms may include:
- abdominal (tummy) pain
- unexplained weight loss
- a lump in the abdomen
- blood in the stools or on the toilet paper
- changes in bowel habits, including diarrhoea or constipation
- feeling sick (nausea) or vomiting
- tiredness and weakness, caused by a low red blood cell count (anaemia)
- yellowing of the skin and eyes (jaundice).
Small bowel neuroendocrine tumours can develop slowly and may not cause symptoms. If you do have symptoms it will depend on where in the body the tumour is and whether the tumour cells are producing hormones.
Some neuroendocrine tumours that are more advanced produce excess hormones (such as serotonin) that can cause a group of symptoms known as carcinoid syndrome. Symptoms may include facial flushing, diarrhoea, wheezing and, rarely, carcinoid heart disease leading to shortness of breath.
If your doctor thinks that you may have small bowel cancer, they will perform a physical examination and carry out certain tests. If the results suggest that you may have small bowel cancer, your doctor will refer you to a specialist who will carry out more tests.
Further tests a specialist may carry out include:
- Blood tests – including a full blood count and liver function tests. You may also have a chromogranin A (CgA) blood test to help diagnose a carcinoid or other neuroendocrine tumour.
- Urine test – to examine if there are any cancer ‘waste’ products excreted into the urine.
- Immunochemical faecal occult blood test (iFOBT) – to examine a stool sample for traces of blood.
- Endoscopy – a flexible tube with a camera on the end (endoscope) is inserted under sedation down the throat into the stomach to view your gut.
- Capsule endoscopy – a procedure where you swallow a small capsule that contains a tiny camera that takes pictures of your digestive tract that are then transmitted to a recorder you wear around your waist. The camera is passed out in your stools about 24 hours later.
- CT (computerised tomography) or MRI (magnetic resonance imaging) scans – special painless machines are used to scan and create pictures of the inside of your body.
- PET (positron emission tomography) scan – you will be injected with a small amount of radioactive glucose (sugar) solution to help cancer cells show up brighter on the scan. Sometimes a Dotatate-PET scan will be needed to find and diagnose neuroendocrine tumours, which involves a small amount of a radioactive drug call Dotatate rather than a radioactive glucose.
- Biopsy – removal of some tissue from the affected area for examination under a microscope. In the small bowel, a biopsy can be done during an endoscopy or if it can’t be reached, a surgical biopsy is done under general anaesthesia.
- Barium x-ray – also called upper GI series with small bowel follow-through, you will be given a chalky barium liquid to drink which coats the inside of the bowel and can show any signs of cancer when an x-ray is taken. X-rays may be taken over a few hours as the barium travels to the end of the small bowel.
Finding a specialist
Rare Cancers Australia have a directory of health professionals and cancer services across Australia. The Australia and New Zealand Sarcoma Association (ANZSA) can be contacted for a directory of specialists in sarcoma care and treatment. NeuroEndocrine Cancer Australia can be contacted for a directory of specialists in NET care and treatment.
You will be cared for by a multi-disciplinary team (MDT) of health professionals during your treatment, which may include a surgeon, radiation oncologist, gastroenterologist and dietitian, among others.
Discussion with your doctor will help you decide on the best treatment for your cancer depending on:
- the type of cancer you have
- where it is in your body
- whether or not the cancer has spread (stage of disease)
- your age, fitness and general health
- your preferences.
The main treatments for small bowel cancer include surgery and chemotherapy. Often medications are used that block cancer cells from secreting hormones and chemicals. These treatments can be given alone or in combination.
After treatment for small bowel cancer (especially surgery), you may need to adjust to changes in the digestion and absorption of food, or bowel function. These changes may be temporary or ongoing, and may require specialised help. If you experience problems, talk to your GP, specialist doctor, specialist nurse or dietitian.
Complementary therapies are designed to be used alongside conventional medical treatments (such as surgery) and can increase your sense of control, decrease stress and anxiety, and improve your mood.
Surgery is the main treatment for small bowel cancer (adenocarcinoma, sarcoma and neuroendocrine tumours), especially for people with early-stage disease who are in good health. It is not usually recommended for lymphomas in the small bowel – these are commonly treated with radiation therapy and/or chemotherapy.
The way the surgery is done depends on the location and stage of the tumour. You may have open or keyhole surgery. Surgical procedures for small bowel cancer include a resection or bypass.
A resection is the surgical removal of part of the small bowel that contains cancer. Surrounding lymph nodes and nearby organs (stomach, large bowel, gall bladder) may also be removed during the procedure. It includes:
- Right Hemicolectomy – removes the right side of the large bowel and the end of the ileum.
- Whipple procedure – removes the pancreas, the duodenum, the gall bladder and bile duct. Also called pancreaticoduodenectomy.
A bypass is a surgical connection to allow digested food in the small bowel to go around the cancer if it is blocking the bowel and cannot be removed.
Side effects of surgery may include bleeding, damage to nearby tissue and organs (including nerves), pain, infection, blood clots, weak muscles and lymphoedema.
If part of the bowel is removed during surgery, the surgeon will usually join it back together. This join is called an anastomosis. If this isn’t possible, you may need a stoma, where the end of the intestine is brought through an opening made in your abdomen to allow faeces to be removed from the body and collected in a bag. The stoma may be temporary or permanent. For more information, visit the Australian Association of Stomal Therapy Nurses.
Chemotherapy is often used to treat lymphomas in the small bowel. Your treatment will depend on your situation and the type of cancer you have. Your medical oncologist will discuss your options with you.
Chemotherapy is given through a drip into a vein (intravenously) or as a tablet that is swallowed. It is commonly given in treatment cycles which may be daily, weekly or monthly. The length of the cycle and number of cycles depends on the chemotherapy drugs being given.
Common side effects include fatigue, loss of appetite, nausea, bowel issues such as constipation or diarrhoea, hair loss, mouth sores, skin and nail problems, increased chance of infections and loss of fertility.
Immunotherapy or biological therapy uses the body’s own immune system to fight cancer. It uses materials made either by the body or in a laboratory to improve immune system function. There are different types of immunotherapy available so talk to your doctor about what might be appropriate for you.
External beam radiation therapy
uses high energy rays to destroy cancer cells, where the radiation comes from a machine outside the body. It may be used for small bowel cancer:
- before or after surgery, to destroy any remaining cancer cells and stop the cancer coming back
- if the cancer can’t be removed with surgery
- if the cancer comes back in a limited way, such as only in your abdominal lymph glands.
Radiation therapy can shrink the cancer down to a smaller size. This may help to relieve symptoms such as pain or blood loss.
A course of radiation therapy needs to be carefully planned. It does not hurt and is usually given in small doses over a period of time to minimise side effects, which may include fatigue, loss of appetite, nausea, bowel issues such as diarrhoea, abdominal cramps and excess wind, bladder issues, skin problems, lymphoedema and loss of fertility.
Asking your doctor questions will help you make an informed choice about your treatment and care. You may want to include some of the questions below in your own list:
- What type of small bowel cancer do I have?
- How far has the cancer spread? What stage of cancer do I have?
- Have you treated this type of cancer before?
- What are the treatment options for me? What do you recommend and why?
- If an operation is recommended, how many times have you performed it?
- Is there another doctor who has more experience treating this type of cancer?
- Will I need a stoma? If so, will it be temporary or permanent?
- What are the possible risks and side effects of my treatment? How will these be managed?
- How long will treatment take?
- What complementary therapies might help?
- Is this treatment covered by Medicare/private insurance? Will there be extra expenses?
- What are the possible benefits and risks to joining a clinical trial? What is being tested and why? How many people will be involved in this trial?
Life after treatment
Once your treatment has finished, you will have regular check-ups to confirm that the cancer hasn’t come back. Ongoing surveillance for small bowel cancer involves a schedule of ongoing scans and physical examinations. Maintaining a healthy body weight, eating well and being active are all important.
For some people small bowel cancer does come back after treatment, which is known as a recurrence. This is why it’s important to have regular check-ups. If the cancer does come back, treatment will depend on where the cancer has returned to in your body and may include a mix of surgery, radiation therapy and chemotherapy.
In some cases of advanced cancer, treatment will focus on managing any symptoms, such as pain, and improving your quality of life without trying to cure the disease. This is called palliative treatment.
Understanding Small Bowel Cancer
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Expert content reviewers:
Prof David Goldstein, Medical Oncologist, Prince of Wales Hospital, Sydney, NSW; Craig Lynch, Colorectal Surgeon, Sydney Adventist Hospital, Sydney; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Wayne Reynolds, Consumer; Dr Stephen Thompson, Radiation Oncologist, Prince of Wales Hospital, Sydney, NSW.
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The information on this webpage was adapted from Understanding Small Bowel Cancer - A guide for people affected by cancer (2021 edition). This webpage was last updated in September 2021.