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Small Bowel Cancer – 2016

UPDATED NOVEMBER 2016

1. General information

1.1 What is the disease and how is it treated?

What is small bowel cancer?
The small bowel is the part of the digestive system which links the stomach to the colon. It is divided into duodenum, jejunum, and ileum.
Tumours of the small bowel may be either benign (non cancerous), such as polyps and lipomas, or malignant (cancerous).
Small bowel cancer (SBC) starts with a group of cells growing out of control and forming a mass. There are more than 40 different tumours occurring in the small bowel.
It is worth noting that the small bowel rarely develops malignant tumours

How does SBC manifest itself?
Often SBCs manifest themselves through non-specific signs, such as abdominal pain, nausea, vomiting, weight loss, anaemia, or bleeding. The same symptoms may be associated with conditions less serious than cancer, such as irritable bowel disease or inflammatory bowel disease.

What are the causes of the disease?
Alcohol consumption and smoking are a risk factor for SBC.
Even diet is a factor that can lead to small bowel cancer, especially high intake of sugar, refined carbohydrates, red meat, or smoked food.
A recent study found that a high body mass index and menopausal hormone therapy could cause malignant carcinoid tumours.
A small portion of small bowel cancers is linked to genetic predisposition or chronic inflammatory disorders.

Is it a frequent disease?
Small bowel cancer is a rare disease. In the period 2000-2007, 8 persons per million every year were diagnosed with SBC in Europe.

How is it diagnosed?
Diagnosing SBC can be difficult, both because of the bowel’s position in the middle tract of the digestive system and the way it is folded. When SBC is suspected, a series of tests can help the diagnosis: barium X-ray, blood tests, endoscopy or colonoscopy, and CT scans.

How is it treated?
Surgery is the treatment of choice and it is the only therapeutic modality with curative potential. In advanced, unresectable disease, options include palliative resection and bypass.
Radiotherapy or chemotherapy (or their combination) may be used after surgery.

2. What is it, how does it occur, how is it diagnosed?

2.1 What is small bowel tumour?

The small bowel is the longest part of the digestive system (about 7 metres long) which links the stomach to the colon. It is divided into duodenum, jejunum, and ileum. Here, digestion and absorption of food take place.
Small bowel cancer starts with a group of cells growing out of control and forming a mass.
There are more than 40 different tumours occurring in the small bowel; the most common are:

  • adenocarcinomas (40%): the most common malignant tumours of the small bowel, usually occurring in the duodenum or in the jejunum, they start in the lining of the bowel;
  • carcinoid (or neuroendocrine) tumours (36%): generally occurring in the ileum, they start in the cells that produce hormones inside the small bowel;
  • lymphomas (10%): mostly non-Hodgkin lymphomas, usually occurring in the jejunum or in the ileum, lymphomas start in the lymph tissue;
  • sarcomas: generally occurring in the ileum, they arise in the muscle tissue.

Despite the fact that the small bowel represents 75% of the total length of the gastrointestinal tract and more than 90% of the mucosal surface, it rarely develops malignant tumours. The reasons for this low incidence, particularly compared to the colon-rectum, are unknown. Maybe the higher cell turnover, the fast transit of intestinal content, and the low bacterial load are mechanisms that decrease the susceptibility for neoplastic transformation. Furthermore, the epithelial cells of the small bowel are equipped with a wide range of enzymes that may protect them from food-derived carcinogens.

2.1.1 Disease stats

Frequency
In the period 2000-2007, European incidence [number of new cases in a year] was 8 x1,000,000 people per year (i.e., in Europe 8 persons in a million every year were diagnosed with a small bowel cancer). SBC is diagnosed mainly in people over 65, while it is very rare under 40 years of age.
The increase in incidence recorded between 1999 and 2007, from 6 to 8 per million/year, was more marked in men.

Geographical distribution
Eastern European countries show the lowest incidence of SBC, the UK and Ireland the highest.

Prevalence
In Europe, about 13,300 people live with a diagnosis of SBC. About 3 every 10 of these persons are long survivors.

Survival
Among the adults diagnosed in the years 2000-2007, 51% were alive 1 year after diagnosis, and 27% after 5 years. Survival decreases with age. One- and 5-year survival have improved since the late 1990s.

2.2 Risk factors

For most SBCs the causes are unknown, but a number of factors may increase the risk of their development; among them:

  • high intake of fats, sugar, refined carbohydrates, red meat, or smoked food;
  • genetic predisposition:
    • familial adenomatous polyposis: a rare inherited condition in which polyps grow on the lining of the colon;
    • Lynch syndrome: a rare inherited condition that increases the risk of developing several types of cancer;
    • Peutz-Jegher syndrome: an inherited condition which causes benign polyps to form in the bowel;
  • chronic inflammatory disorders:
    • Crohn’s disease: a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus;
    • coeliac disease [an immune response that attacks the small intestine when eating gluten.

A recent study found that a high body mass index and menopausal hormone therapy could cause malignant carcinoid tumours.
Alcohol consumption and smoking have also been linked to the risk of SBC.

2.3 What are the symptoms?

Typical symptoms of small bowel cancer are:

  • pain or cramps in the abdomen;
  • a lump in the abdomen;
  • unexplained weight loss;
  • episodes of nausea and vomiting after abdominal pain;
  • anaemia, due to blood loss;
  • dark or bloody stools, due to bleeding in the small bowel consequent to a perforation or obstruction;
  • diarrhoea.

As these symptoms are not specifically linked only to small bowel cancer, a person who experiences these changes must refer to his/her doctor to find the correct diagnosis, particularly if the symptoms are severe, worsen, or last for a long time.

2.4 Diagnosis

The mean time to diagnosis of small bowel cancer, from the patient’s initial complaint, is 7 months. No single diagnostic procedure is considered as the gold standard.
Depending on the symptoms, the doctor may diagnose the type of disease: benign tumours may remain asymptomatic, while adenocarcinomas are associated with abdominal pain, weight loss, and obstruction; sarcomas are associated with haemorrhage, lymphomas with perforation.
Your doctor may refer you to a specialist, who will ask you about your general health and will examine a blood sample to check for anaemia.
For most types of cancer, a biopsy may be requested.
Other useful tests are the following:

  • endoscopy is used to check inside the duodenum and the upper part of the jejunum and, if necessary, to take a tissue sample;
  • video capsule endoscopy: the patient swallows a capsule the size of a pill, which remains in the patient’s body for about 8 hours. The camera located inside the capsule enables doctors to see obscure gastro-intestinal bleeding and obstructions;
  • colonoscopy makes it possible to check inside the lower part of the small bowel and, if necessary, take a tissue sample;
  • Computed Tomography (CT) scan: through X-rays, a three-dimensional image of the inside of the body is created, allowing the doctor to see abnormalities or tumours and also to evaluate tumour size.
  • Positron emission tomography (PET) or PET-CT scan: the patient is injected with a small amount of radioactive sugar which is taken up by the cells that use the most amount of energy. The scan detects the cells which absorb the greatest amount of this radioactive substance (usually cancer cells), producing images of the inside of the body.
  • laparotomy: the abdomen is surgically incised to check for the disease, to take a sample or, if necessary, to remove the tumour.

3. Stages of Small bowel cancer

The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification to define small bowel cancers.

Table 1. Classification of primary tumours (T).
Tx Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis Carcinoma in situ
T1a Tumour invades the lamina propria
T1b Tumour invades submucosa
T2 Tumour invades muscolaris propria
T3 Tumour invades through the muscularis propria into the subserosa
or into the non-peritonealised perimuscular tissue (mesentery or retroperitoneum) with extension ≤2 cm
T4 Tumour perforates the visceral peritoneum or directly invades other organs
or structures (it includes other loops of the small intestine, mesentery, or retroperitoneum>2 cm,
and abdominal wall by way of the serosa; for duodenum only, invasion of pancreas or bile duct).
Table 2. Classification of regional lymph nodes (N).
Nx Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastases in 1-3 regional lymph nodes
N2 Metastases in ≥4 regional lymph nodes
Table 3. Classification of metastases (M).
Mx Distant metastases cannot be assessed
M0 The cancer has not spread
M1 The cancer has spread to a part of the body other than the primary site of the tumour
Table 4. Anatomic stage and prognostic groups.
Anatomic Stage Prognostic group
Primary tumour (T) Regional lymph node (N) Metastasis (M)
0 Tis N0 M0
I T1 N0 M0
T2 N0 M0
IIA T3 N0 M0
IIB T4 N0 M0
IIIA Any T N1 M0
IIIB Any T N2 M0
IV Any T Any N M1

4. How is Small bowel cancer treated?

4.1 General information

Treatment of small bowel cancer depends on the type of cancer, the cancer’s size, and the general health of the patient. The presence of metastases [cancer cells that have spread] also needs to be considered.
Since small bowel cancers are rare, there is limited scientific evidence on best treatment options.

4.2 Surgery

Surgery is the treatment of choice and the only one with curative potential. It may be used to remove the tumour, to join the bowel, and/or to bypass obstructions, where present.
Depending on the size of the tumour and the presence of metastases, the extent of the surgery may vary: the surgeon may need to remove part of the stomach, and/or of the colon, and/or the surrounding lymph nodes.
Duodenal tumours may require pancreaticoduodenectomy; polypoid lesions confined in the mucosa can be cured by endoscopic resection.
In cases of advanced unresectable disease, the options to choose from are bypass or palliative resection.
The side effects of surgery may include pain in the treated area, constipation, and/or diarrhoea.

4.3 Chemotherapy

Chemotherapy for jejunal or ileal adenocarcinomas and adjuvant chemotherapy for duodenal cancer may be given to the patient, but no meaningful improvement in survival has been shown.
The main choice for chemotherapy is 5-fluorouracil (known as 5-FU); the combination of 5-FU and Oxaliplatin is used for adjuvant chemotherapy. For advanced small bowel adenocarcinomas, 5-FU in combination with Platinum is considered the best choice.
The side effects of chemotherapy depend on the individual and the dose used; in general, they can include fatigue, risk of infection, nausea and vomiting, hair loss, loss of appetite, and diarrhoea. These side effects usually go away once treatment is finished.

4.4 Radiotherapy

Radiotherapy is not often used as primary treatment for small bowel cancer, but may be used after surgery or in combination with chemotherapy.
Side effects from radiation therapy include tiredness, mild skin reactions, upset stomach, and loose bowel movements. Most side effects go away once treatment is finished.

4.5 Carcinoid (or neuroendocrine) tumours

The treatment of choice for this type of small bowel cancer is segmental resection with lymph node draining (because of its locoregional spread).
If metastases are present, resection of the primary tumour and cytoreductive therapy (surgery or radiation therapy) are suggested. It is worth noting that the liver is the most common site of metastases, so it should be resected with the primary tumour.
For this type of small bowel cancer, the role of chemotherapy remains unclear. In 2017, an immunosuppressant called Everolimus will be included in treatment of cases with well-differentiated histology, since it has shown good results.

5. Prognosis

5.1 General information

Prognosis indicates the likelihood that treatment will be successful. It is a statistical measure obtained from different studies observing the progress of the disease in a high number of patients.
It is important to keep in mind that no doctor is able to predict exactly what the outcome of the treatment in an individual patient will be, nor how long a patient will live, as prognosis depends on the individual patient and several factors.

5.2 Prognosis of small bowel cancer

Overall 5-year survival is 22%-30%. Median survival is 19 months. It must be considered that many people live much longer than 5 years.
People with duodenal carcinoma reported better survival.
According to cancer stage, survival rates are the following:

  • stage I: 65%;
  • stage II: 48%;
  • stage III: 35%;
  • stage IV: 4%.

5.3 Prognostic factors

Individual factors, such as age and gender, are impossible to assess, because of the rarity of the disease.
The first thing that significantly affects prognosis of small bowel cancer is staging: the larger and deeper the cancer is, the lower the survival rate.
People with obstruction or perforation of the small bowel have a worse outlook; the same is true of patients with positive lymph node involvement.

6. What to do after treatment

6.1 Follow-up

There is no specific information about follow-up for small bowel cancer.
After the end of treatment, patients must schedule regular check-ups with their doctor. The tests used to diagnose the disease may be repeated in order to see the results of treatment (i.e., to check if cancer has come back or spread, and to look for side effects).
Doctors may also refer patients to a clinical trial to get state-of-the-art treatment and, in some cases, access to newer types of treatment.

 7. What to ask doctors

Here is a list of questions that you might wish to ask your doctor or any specialists you may consult. To avoid unnecessary concern, it is useful to ask about any doubts you might have, no matter how small they may appear.

General questions

• May I phone you? What is the best time? If you are not available, may I ask for other specialists? Whom specifically?
• What leaflets, books, or websites could I read to learn more about small bowel cancer?
• Is there a patient association or online support group I could contact?
• Should I pay special attention to activities such as sports?
• Do you have special advice regarding nutrition?
• Does small bowel cancer run in families? Are my children at risk of getting it?
• Can you refer me for counselling?

Diagnosis and exams

• What type of tumour is it?
• What tests are you going to do?
• What are you looking for?
• How long will the exam take?
• Is biopsy painful? Is it performed under general or local anaesthesia?
• Is CT dangerous because of radiation exposure?
• Will I be asleep?
• How long will it take to confirm diagnosis?
• Can you explain my laboratory test result to me?
• What is the stage of cancer and what does it mean?
• What is the risk group and what does it mean?

Treatment

• What should I do to be ready for treatment?
• Do I need a highly specialized centre?
• What other doctors will I see?
• What type of treatment is needed?
• Is there any choice of treatment?
• Will I pay for treatment? What is it likely to cost?
• What type of surgery will you perform? Can you describe it?
• What are the risks and benefits of treatments?
• How long will treatment last? Where will it be done?
• Will I need to follow a special diet? Will I have to take supplements to aid digestion?
• Will treatment reduce symptoms and discomfort?
• What are the possible side effects of therapy? Will I lose my hair, or have nausea and vomiting?
• How can I help to reduce the side effects?
• During treatment, should I take special precautions or change any habits?
• Which supportive therapy is suggested during treatment?
• How will treatment affect me?
• How will treatment affect my daily life?
• Will I be able to work and perform my usual activities?
• Will treatment affect my sex life or ability to have children?
• How long will it take to recover?
• What follow-up will be needed after treatment?
• What late effects could treatment have?
• Will treatment increase the risk of other cancer in the future?
• Could small bowel cancer recur?
• What is the outlook for cure?
• Should I participate in a clinical trial? If so, in what trial?