Small bowel cancer, also known as small intestine cancer, is a rare malignancy that develops in the small bowel/intestine. The small bowel is a long tube that carries food from your stomach to the large bowel/intestine.
The small bowel is located towards the end of the body’s gastrointestinal (GI) tract, which is located in the abdomen. The lower GI tract is divided into three separate areas: the small bowel, the large bowel, and the anus. The small bowel receives food from the stomach and absorbs the nutrients from the food. It is comprised of three separate parts (the duodenum, jejunum, and ileum). The food is then passed onto the large bowel, where water and salts are absorbed. The large bowel also consists of three parts (the caecum, colon, and rectum). What is left over is turned into solid waste (faeces or stool), and is sent to the anus to be removed from the body.
Small bowel cancer is more common in men, and is generally diagnosed in patients over 60 years old. However, anyone can develop this disease.
Types of Small Bowel Cancer
There are several types of small bowel cancers, which are categorised by the types of cells they originate in.
Adenocarcinomas
Small bowel adenocarcinomas are the most common form of small bowel cancer. They start in the cells that line the mucus-producing glands in the small bowel, usually in the duodenum segment. This type of cancer is less aggressive than other subtypes of small bowel cancer, and can have a good prognosis when caught early.
Gastrointestinal Stromal Tumours (GISTs)
A gastrointestinal stromal tumour (GIST) is a rare type of sarcoma (cancer arising from bones or soft tissues) that forms in lining of the gastrointestinal tract. More specifically, they develop in interstitial cells of Cajal (ICC), which play a critical role in the intestinal contractions required for digestion. For more information on GISTs, please refer to the Rare Cancers Australia Gastrointestinal Stromal Tumours (GIST) page.
Leiomyosarcomas
Leiomyosarcomas are a type of sarcoma (cancer arising from bones and/or soft tissue) that develops in the muscles. While rhabdomyosarcomas develop in skeletal muscles, leiomyosarcomas develop in smooth muscles, which form walls of organs, glands, and blood vessels within the body. They often develop in the ileum of the small bowel, and can be aggressive. Leiomyosarcomas can have a good prognosis when caught early. For more information on leiomyosaromas, please refer to the Rare Cancers Australia Leiomyosarcoma page.
Carcinoid Tumours
Carcinoid tumours of the small bowel are a very rare subtype of small bowel cancers that develop from neuroendocrine cells, often in the ileum. Neuroendocrine cells, which are responsible for receiving signals from the nervous system and producing hormones and peptides (small proteins) in response. For more information on gastrointestinal carcinoid tumours, please refer to the Rare Cancers Australia Gastrointestinal Carcinoid Tumour page.
Lymphomas
Small bowel lymphomas are a rare form of small bowel cancer that form from lymphocytes in the jejunum. It is a type of non-Hodgkin lymphoma (cancer of the lymphatic system) that affects the immune system. Small bowel lymphoma can be aggressive, but they can have a good prognosis wen caught early.
Treatment
If small bowel cancer is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodes) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for small bowel cancer may include:
- Surgery, potentially including:
- Right Hemicolectomy (removal of the right side of the large bowel and a portion of the ileum).
- Pancreaticoduodenectomy/whipple procedure (removal of the pancreas, duodenum, gall bladder and bile duct).
- Lymphonodectomy (removal of affected lymph nodes).
- Chemotherapy.
- Radiation therapy.
- Immunotherapy.
- Clinical trials.
- Complimentary therapies.
- Palliative care.
For more information on the treatment options, please refer to the Rare Cancers Australia treatment options page.
Risk factors
While the cause of small bowel cancers remains unknown, the following factors may increase the risk of developing the disease:
- Having certain genetic conditions, such as:
- Familial adenomatous polyposis (FAP).
- Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer or HNPCC).
- Peutz-Jeghers syndrome (PJS).
- Cystic fibrosis (CF).
- Multiple endocrine neoplasia type 1 (MEN 1).
- Having Crohn’s disease.
- Having coeliac disease.
- Having a diet rich in animal fats, proteins, and processed meats.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Early symptoms
Symptoms of small bowel cancers may include:
- Abdominal pain.
- Unexplained weight loss.
- A lump in the abdomen.
- Blood in stools.
- Changes in bowel habits, such as:
- Nausea and/or vomiting.
- Fatigue.
- Anaemia.
- Jaundice (yellowing of the eyes and/or skin).
Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have small bowel cancer, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment.
Physical examination
Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities.
Imaging & blood tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), barium x-ray and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions.
Endoscopy & biopsy
An endoscopy is a surgical procedure that involves inserting a long, flexible tube with a light and small camera through oesophagus and into the stomach. You will be given a sedative or anaesthetic throughout the procedure. You will be asked to fast for several hours prior to the procedure. An endoscopy is often done as a day surgery. Your doctor will discuss the risks and any possible complications prior to the procedure.
Throughout the procedure, your doctor may also perform an endoscopic ultrasound to guide the needle during a biopsy, or to check for signs of cancer metastasis.
If any abnormalities are observed, your doctor will remove a small tissue sample for analysis.
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage small bowel cancers have a better prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.