What is small bowel cancer?
Small bowel cancer (also called small intestine cancer) is cancer that starts in the small bowel.
Clinical Oncologist Katherine Aitkens explains bowel cancer in the video below. She gives an overview of bowel cancer symptoms, diagnosis and treatment.
Small bowel cancer is rare. About 1,800 people in the UK are diagnosed with it each year.
We have more information about other types of bowel cancer including:
The small bowel
The small bowel is part of the digestive system. It is part of the bowel, between the stomach and the large bowel (colon).
The small bowel is about 4 to 6 metres (13 to 19 feet) long. It folds many times to fit inside the tummy (abdomen). The small bowel breaks down food. This allows vitamins, minerals and nutrients to be absorbed into the body.
The small bowel is made up of 3 main parts:
- The duodenum is the top section that joins the stomach. About half of all small bowel cancers (50%) start in the duodenum.
- The jejunum is the middle section.
- The ileum is the lower section that joins the large bowel.
Small bowel with duodenum, jejunum and ileum
Small bowel cancer is rare. About 1,800 people in the UK are diagnosed with it each year.
We have more information about other types of bowel cancer:
Types of small bowel cancer
There are different types of small bowel cancer. They are named after the cells where they develop. The 4 main types are:
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Adenocarcinoma
This is the most common type of small bowel cancer. It starts in the lining of the small bowel, usually in the duodenum.
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Sarcoma
Sarcoma develops in the supportive tissues of the body – for example, fat, muscle and nerves. There are different types of sarcoma. The most common type that affects the small bowel are gastrointestinal stromal tumours (GISTs). GISTs can develop in any part of the small bowel. Another type is leiomyosarcoma. This usually develops in the muscle wall of the small bowel, usually in the ileum.
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Neuroendocrine (carcinoid) tumours
Neuroendocrine tumours (NETs) start from cells that make hormones inside the small bowel. They usually start in the ileum.
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Lymphoma
This starts in the lymph tissue of the small bowel. The lymph tissue is part of the body’s immune system. Small bowel lymphoma is usually non-Hodgkin lymphoma (NHL). It most commonly affects the ileum.
The small bowel cancer information on our website is about adenocarcinoma of the small bowel. This is the most common type. Other types are treated differently. Your cancer doctor or specialist nurse can give you more information.
Secondary cancer in the small bowel
Occasionally, cancer in the small bowel is found to be a secondary cancer. This means it has spread to the small bowel from somewhere else in the body (the primary cancer). The most common cancers that might spread to the small bowel are:
The treatment you have for secondary cancer in the small bowel will depend on the primary cancer. Your cancer doctor and specialist nurse can give you more information.
Related pages
Symptoms of small bowel cancer
Some of the symptoms of small bowel cancer include:
- cramping in the tummy
- weight loss
- and feeling sick.
If the cancer causes a blockage in the bowel this can cause different symptoms.
We have more information about small bowel cancer symptoms.
Related pages
Causes of small bowel cancer
Doctors do not usually know what causes small bowel cancer. But research is being done to try to find out more.
Some people with non-cancerous bowel conditions may have a higher risk of developing small bowel cancer. These conditions include:
- Crohn’s disease
- coeliac disease
- Peutz-Jeghers syndrome.
People who have had colon cancer or rectal cancer have an increased risk of developing small bowel cancer.
People also have a higher risk if they have:
- Lynch syndrome, also called hereditary non-polyposis colorectal cancer (HNPCC)
- familial adenomatous polyposis (FAP).
Like all cancers, small bowel cancer is not infectious and cannot be passed to other people.
Diagnosis of small bowel cancer
Small bowel cancer can be diagnosed in different ways.
If you go to your GP about symptoms such as pain, weight loss or tiredness caused by anaemia, they will examine you. They will also arrange some blood tests or x-rays. They may then refer you to a specialist doctor at the hospital for more tests and treatment.
Some people are diagnosed with small bowel cancer after being admitted to hospital with more severe symptoms – for example, pain caused by a blockage or tear in the bowel.
At the hospital, a specialist doctor will examine you. They may arrange the following tests:
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Blood tests
You usually have blood tests to help with diagnosis and treatment.
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Stool sample
A sample of your poo (stool) is tested for blood. Your doctor or nurse will explain how to collect the sample.
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Endoscopy
An endoscopy is a test that looks inside the body using an instrument called an endoscope. An endoscope is a thin, flexible tube. The tube has a light and a camera at the end. It is passed into the body to help doctors see inside.
This test has different names depending on the area examined. An upper endoscopy uses a tube passed through the mouth. A colonoscopy uses a tube passed through the rectum.
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CT scan
A CT scan uses x-rays to build up a three-dimensional (3D) picture of the inside of the body.
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MRI scan
An MRI scan uses magnetism to build up a detailed picture of areas of your body.
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Capsule endoscopy
This test is sometimes used to diagnose small bowel cancer. A capsule endoscopy is used to take pictures of the whole of the inside of your digestive tract. You swallow a capsule that is the size of a large pill. Inside the capsule there is a camera that takes pictures of the lining of the bowel.
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Other tests
If it is difficult to diagnose small bowel cancer with the endoscopies and scans, you may have an operation to look inside the bowel.
Waiting for test results can be a difficult time. It may take from a few days to a couple of weeks for the results of your tests to be ready. We have more information about waiting for test results that may help.
Related pages
Staging small bowel cancer
The results of your tests help your doctors find out more about the size and position of the cancer and whether it has spread. This is called staging.
Knowing the stage of the cancer helps your doctors plan the best treatment for you.
We have more information about staging adenocarcinoma of the small bowel.
Treatment for small bowel cancer
A team of specialists will meet to discuss the best possible treatment for you. This team is called a multidisciplinary team (MDT). The MDT will look at national guidelines to help plan your treatment.
After the MDT meeting, you will usually meet with your cancer doctor and specialist nurse. They will talk to you about your treatment plan.
Your treatment plan may depend on:
- your general health
- the position and size of the cancer
- whether it has spread to other areas of the body
- your personal choices.
Your doctor will explain the different treatments and their side effects. They will also talk to you about the things you should consider when making treatment decisions.
Surgery
Surgery is the most common treatment for small bowel cancer. You might have surgery on its own or with other treatments.
Surgery involves removing all or part of the cancer with an operation. It is the main treatment for small bowel cancer that has not spread or is not causing problems.
The type of surgery you have depends on the size and position of the cancer, whether it has spread to any surrounding areas and your general health. Your surgeon will explain what type of surgery will be best for you.
We have more information about surgery for small bowel cancer.
Chemotherapy
Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy the cancer cells. For small bowel cancer, it may be used before or after surgery to shrink the cancer and reduce the risk of it coming back.
It may also be used as the main treatment, if the cancer has spread to parts of the body such as the liver or lungs. Sometimes, it may be given with radiotherapy – this is called chemoradiation.
The chemotherapy drugs most commonly used to treat small bowel cancer are:
- fluorouracil (5FU)
- capecitabine (Xeloda®)
- oxaliplatin (Eloxatin®)
- irinotecan (Campto®).
You often have 2 or more chemotherapy drugs at the same time. The most often used combinations are:
- FOLFOX (folinic acid, fluorouracil and oxaliplatin)
- XELOX (CAPOX) (capecitabine and oxaliplatin)
- FOLFOXIRI (folinic acid, fluorouracil, oxaliplatin and irinotecan)
- FOLFIRI (folinic acid, fluorouracil and irinotecan).
Chemotherapy is not suitable for everyone. Your cancer doctor will tell you more about chemotherapy and whether it right for you.
Targeted therapy
Targeted therapy drugs find and attack cancer cells. There are many different types of targeted therapy drug. Each one targets something in or around the cancer cell that is helping it grow and survive.
For small bowel cancer, some people have a drug called bevacizumab along with their chemotherapy. Your doctor will be able to tell you whether this is a suitable treatment for you.
We have more information about targeted therapies and targeted therapy drugs on our Treatments and drugs A to Z page.
Immunotherapy
This treatment is not commonly used for small bowel cancer. But it might be suitable for some people. You might be offered certain immunotherapy drugs if tests on the cancer cells show one of the following:
- The cancer cells are mismatch repair deficient (MMR) or have high microsatellite instability (MSI). This is when the system that stops dividing cells from making mistakes in the DNA is not working properly.
- There is a genetic change (mutation) in the POLE gene. This gene normally helps prevent cancer developing.
The immunotherapy drugs most commonly given for small bowel cancer are pembrolizumab and nivolumab. Your doctor can tell you whether these drugs might be helpful for you. You may be offered immunotherapy as part of a clinical trial.
We have more information about immunotherapy and immunotherapy drugs on our Treatments and drugs A to Z page.
Palliative radiotherapy
Radiotherapy uses high-energy rays to destroy cancer cells. It may be used to shrink the cancer and to help to relieve symptoms such as pain or bleeding. This is called palliative radiotherapy.
Your nurse or doctor will tell you what to expect and explain the possible side effects. Palliative radiotherapy usually involves having only a few treatments. This means the side effects are usually mild.
You may have some treatments as part of a clinical trial.
After small bowel cancer treatment
Follow-up after treatment for small bowel cancer
You will have regular check-ups during and after your treatment. Tell your doctor or specialist nurse as soon as possible if you have any problems or notice new symptoms between appointments.
We have more information about follow-up care after treatment.
Sex life
Small bowel cancer and its treatment can affect your sex life. Changes may get better over time, but sometimes they are permanent. If you have any problems or are worried about this talk to your doctor or nurse. They can explain what to expect and there are often things that can help.
Support after small bowel cancer
People often have many different feelings when they finish small bowel cancer treatment. You may feel relieved that treatment has finished, but worried about what will happen in the future.
We have information below about some of the things people ask about after small bowel cancer treatment. But you may have other questions or need information about something else.
Macmillan is here to support you. If you would like to talk, you can:
- call the Macmillan Support Line for free on 0808 808 00 00
- chat to our specialists online
- visit our bowel (colon and rectal) cancer forum to talk to people who have been affected by bowel cancer, share your experience, and ask an expert your questions.
Other organisations who offer information and support include:
Well-being and recovery
It can take time to recover after small bowel cancer treatment. Some days you may feel better than others.
Looking after yourself can help speed up your recovery. Even small lifestyle changes may improve your well-being.
Even if you already have a healthy lifestyle, you may choose to make some positive changes after treatment. We have more information on leading a healthy lifestyle after treatment.
It is important to know where to get support or information if you need it. People often need support even some time after small bowel cancer treatment. But sometimes it is difficult to know who to ask for help. To find support:
- ask your GP or someone from your cancer team for advice about support in your area
- search cancercaremap.org to find cancer support services near you
- call us free on 0808 808 00 00 or talk to us talk to us online - our cancer information and support specialists can offer guidance and help you find what you need.
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
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References
Below is a sample of the sources used in our small bowel cancer information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
JC Cusack, MJ Overman, H Kunitake. Treatment of small bowel neoplasms. UpToDate 2023.
AB Benson, AP Venook, MM Al-Hawary et al. Small Bowel Adenocarcinoma, Version 1.2020, NCCN Clinical Practice Guidelines in Oncology. Journal of the National Comprehensive Cancer Network, 17(9), 1109-1133. Available from: www.jnccn.org [accessed January 2023].
National Institute for Health and Care Excellence (NICE). Wireless capsule endoscopy for investigation of the small bowel. Published: 15 December 2004. Available from: www.nice.org.uk/guidance/ipg101 [accessed January 2023].
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