Small Intestine Cancer
Small bowel cancer refers to a group of malignant lesions that can be seen all across the small intestine. Between the stomach and the large intestine is the small intestine. To the level of the ileocecal valve, which gives the terminal transition point between the small intestine and the colon, it is divided into three sections: duodenum, jejunum, and ileum. Despite the fact that both benign and malignant tumors can be seen throughout the small intestine, the overall incidence of small bowel malignancies is exceedingly low when compared to lesions found elsewhere in the gastrointestinal system. The majority of these lesions cause a variety of nonspecific symptoms, which can lead to a late diagnosis and, as a result, a delay in implementing potential treatment strategies. Abdominal pain, anorexia, gastrointestinal hemorrhage, and weight loss are all common symptoms. Perforation, small bowel obstruction, or obstructive jaundice are signs of more advanced diseases. Laboratory tests, radiographic imaging, and endoscopic evaluation are used to make a diagnosis, which varies depending on the location of the disease under investigation. Lymphomas, neuroendocrine tumors, adenocarcinomas, and stromal tumors are all malignant tumors.
What is a Small Intestine Cancer?
When cells within the body begin to grow out of control, cancer develops. Cancerous cells can arise in almost any part of the body and spread to other parts of the body.
When cells in the small intestine begin to grow out of control, small intestinal cancer develops. The gastrointestinal (GI) tract, often known as the digestive tract, includes the small intestine. The GI tract converts food into energy and eliminates waste from the body.
Despite the fact that the small intestine makes up the bulk of the GI tract, small intestinal cancers are far less prevalent in the United States than most other forms of GI cancers (such as colonic, rectal, gastric, and esophageal cancers).
Small Intestine Cancer Types
Because the small intestine is made up of a variety of cell types, many cancers can begin here. The following are the four main forms of small intestinal cancers:
- Adenocarcinoma. These malignancies begin in the gland cells that line the intestines' lumen. They account for roughly one-third of all small intestinal malignancies.
- Carcinoid tumors. Carcinoid tumors are a form of neuroendocrine tumor that grows slowly. Small intestinal tumors of this sort are the most prevalent.
- Lymphoma. They are malignancies that begin in immune cells known as lymphocytes. Lymphomas can develop in almost any part of the body, including the small intestine.
- Sarcoma. They are tumors that begin in the connective tissues of the body, such as the muscle. Gastrointestinal stromal tumors (GIST) are the most prevalent sarcomas in the intestine.
Most specialists believe that small intestine cancer develops similarly to colorectal cancer. It starts as a polyp, a tiny protrusion on the inner lining of the intestine. A polyp can develop into a malignancy over time.
The duodenum is where most intestine cancers (particularly adenocarcinomas) start. Cancers of the duodenum are frequently discovered near the Ampulla of Vater. However, because the Ampulla of Vater is directly linked to the pancreas, tumors of this area are treated similarly to pancreatic cancer.
How Common is Small Intestine Cancer?
Despite the fact that the small intestine makes up a large portion of the gastrointestinal (GI) tract, malignancies of the small intestine are uncommon in the United States. They account for less than one out of every ten malignancies of the gastrointestinal (GI) tract, and less than one out of every 100 cancers in general. Cancers of the small intestine are more common among the elderly. People in their 70s and 80s are the most likely to develop them.
Small Intestine Cancer Risk Factors
A risk factor is something that increases the likelihood of getting a disease like cancer. The risk factors for various malignancies vary. Some risk factors, like smoking, are modifiable. Others, like an individual’s age or case history, are unchangeable.
However, risk factors do not provide complete information. Having one or more risk factors doesn’t guarantee that an individual will develop the disease. Furthermore, many individuals who have the condition have little or no established risk factors.
Because small intestine adenocarcinoma is so rare, it's been difficult to discover its risk factors. The following are a number of the known risk factors:
- Gender. Men are slightly more likely than women to have small intestinal cancer.
- Age. Cancers of the small intestine are more common among the elderly. People in their 70s and 80s are the most likely to develop them.
- Race/ethnicity. African Americans are more likely than individuals of other ethnicities to be affected by these cancers in the United States.
- Smoking and alcohol consumption. Some research has found that smoking or drinking alcohol increases the risk of cancer, although not all investigations have found this.
- Diet. According to several studies, eating a diet high in red meat and salty or smoky foods may increase the chance of developing small intestine cancer.
- Celiac disease. Gluten causes the body's immune system to attack the gut lining in patients with celiac disease. People with celiac disease are more likely to develop enteropathy-associated T-cell lymphoma, a type of intestinal lymphoma. They may also be at a higher risk of developing small intestine cancer.
- Colon cancer. People who have had colon cancer are more likely to have small intestinal cancer. It's possible that this is related to common risk factors.
- Crohn's disease. it is an autoimmune disease in which the immune system destroys the GI tract. This condition can affect any section of the GI tract, although the lower part of the small intestine is the most commonly affected. This disease puts people at a substantially higher risk of developing small intestinal cancer (particularly adenocarcinoma). The ileum (the last part of the small intestine) is the most common site for these malignancies.
- Inherited syndromes. Small intestine cancer is more common in those with specific hereditary disorders (mainly adenocarcinoma).
- Familial adenomatous polyposis (FAP). Many polyps form in the colon and rectum in this syndrome. One or more of these polyps will develop cancer if the colon is not resected. Polyps can also form in the stomach and small intestine, and these polyps can increase the risk of cancer. The duodenum is where most small intestinal malignancies are discovered in FAP. This disorder is caused by a mutation in the APC gene.
- Lynch syndrome (hereditary nonpolyposis colorectal cancer, or HNPCC). A deficiency in one of multiple mismatch repair (MMR) genes, including MLH1, MSH2, MSH6, PMS1, or PMS2, is the most common cause of this syndrome. Any of these genes with an atypical version lowers the body's ability to repair DNA damage. This increases the chance of colon and small intestine cancer, as well as a high risk of endometrial and ovarian cancer.
- Peutz-Jeghers syndrome (PJS). Polyps appear in the stomach and intestines, as well as the nose, the lungs, and the bladder in people who have this disorder. Dark spots on the lips, inside cheeks, and other places are also possible. Many forms of cancer, including small intestine cancer, are linked to PJS. Mutations in the STK11 gene cause this condition.
- MUTYH-associated polyposis. Colon polyps form in people with this disease, and if the colon is not removed, they almost always turn malignant. They are also more likely to develop polyps in the small intestine and have a higher chance of developing small intestine cancer. Cancers of the skin, ovary, and bladder are also possible in people with this disease. Mutations in the MUTYH gene cause this condition.
- Cystic fibrosis. This disorder causes serious lung issues in those who have it. In people with CF, the pancreas frequently fails to produce the enzymes needed to break down food so that it can be absorbed. Small intestine cancer is more common in people with CF. To get CFTR, a kid needs two defective copies of the CFTR gene (one from each parent).
What Causes Small Intestine Cancer?
While various risk factors for small intestinal adenocarcinoma have been identified, little is understood about what causes these tumors. Many experts are baffled as to why it is so uncommon. Despite the fact that the small intestine is the longest section of the gastrointestinal (GI) tract, it is only the site of a small fraction of GI adenocarcinomas.
Inside small intestine adenocarcinoma cells, scientists discovered several DNA alterations that appear to promote their growth and spread. DNA is the molecule that builds up our genes, which determine how our cells function. Because our DNA comes from our parents, we usually appear as if them. However, DNA has an impact on more than our looks.
Some genes regulate when cells divide and expand into new cells:
- Oncogenes aid in cell growth and division.
- Tumor suppressor genes assist in maintaining cell division under control, force cells to die at the appropriate moment, and assist repair DNA mistakes.
DNA alterations that turn on oncogenes or turn off tumor suppressor genes can increase the risk of cancer.
Problems with tumor suppressor genes, which typically help repair damaged DNA, are suspected to be one cause of these tumors. When one of these genes malfunctions, DNA errors go uncorrected, and gene mutations are passed on to subsequent cells. It is possible to develop cancer if enough alterations occur within the cells.
Many small intestine cancer has specific recognized gene mutations, although the origin of these changes isn't always evident. They might be inherited from a parent, or they can be brought on by things like alcohol or a high-red-meat diet. However, gene alterations that cause small intestine cancer might happen for no obvious reason. Many of the changes are likely to be random events that occur inside a cell without any external cause.
Gene alterations inside cells can accumulate over time, which may explain why small intestine cancer primarily affects the elderly.
Symptoms of Small Intestine Cancer
Except for neuroendocrine tumors, which might present with symptoms specific to the products secreted from the neurosecretory granules housed within the malignant cells, the majority of small intestinal malignancies have comparable clinical presentations. Three of the main presenting clinical symptoms are nonspecific mid abdominal pain, significant weight loss, and gastrointestinal bleeding. The abdominal pain is usually described as periodic intestinal cramps, with nausea and vomiting occurring in a small percentage of cases. Larger neoplastic lesions might cause more serious complications including acute small intestinal obstruction or perforation, with obstruction occurring more frequently than perforation. The uncertainty of the presenting symptoms frequently causes diagnostic latency. The degree of cancer involvement or presenting symptoms can influence the physical exam findings.
Because of the production of bioactive chemicals from the initial tumor, neuroendocrine tumors that have metastasized to the liver can cause a slew of symptoms. As a result, assessing biomarkers to confirm the origin of the patient's nonspecific symptoms is part of the workup for such lesions. Carcinoid syndrome is characterized by cutaneous flushing, diarrhea, and less common symptoms such as venous telangiectasias and intermittent respiratory symptoms owing to bronchospasms.
Small Intestine Cancer Diagnosis
If the doctor suspects you of having small intestinal cancer, he or she will most likely prescribe a series of blood tests, including:
- Complete blood count (CBC). The amounts of red blood cells, white blood cells, and platelets are measured in a CBC. Small intestine cancer frequently causes gastrointestinal bleeding, which might result in a low red blood cell count (anemia).
- Blood chemistry. Tests of blood chemistry to look for evidence of cancer spreading to the liver or other issues.
Imaging tests provide images of the inside of the body using x-rays, magnetic fields, or radioactive substances. Imaging tests may be performed for a variety of purposes, including the following:
- To see if a tumor is the source of the symptoms.
- to find out how far cancer has spread.
- To assist in determining whether or not treatment is effective.
- To search for indicators of a recurrence of cancer.
Barium X-ray Test
These tests involve injecting a liquid containing barium into the body to coat the GI tracts' lining, followed by x-rays. The barium helps to draw attention to any abnormalities in the esophagus, stomach, or intestines. These x-rays are most commonly used to detect malignancies in the upper or lower GI tract; however, they are less effective in detecting tumors in the small intestine. Before endoscopy, barium tests were used more often.
- Upper GI series. You will be given a barium beverage to consume before having x-rays taken of the upper part of your digestive tract (the esophagus, stomach, and first part of the small intestine). More x-rays can be obtained over the next few hours as the barium moves through the intestines to look for issues in the rest of the small intestine. A small bowel follow-through is what it's termed. The initial portion of the small intestine (the duodenum) is frequently well-imaged, while the rest of the small intestine might be difficult to observe in detail.
- Enteroclysis. Compared to the upper GI series with small bowel follow-through, this test provides a more thorough view of the small intestine. A tiny tube is inserted into the small intestine through the nose or mouth, stomach, and small intestine. The barium is then injected straight into the small intestine via the tube. As the liquid passes through the small intestine, X-rays are collected.
- Barium enema. This is a technique for examining the colon and rectum. The bowel must be cleared out before this examination. The night before and the morning of the test, strong laxatives and enemas are used to achieve this. The barium solution is injected into the large intestine using a flexible tube that is inserted into the anus. Air can also be introduced into the colon through a tube for sharper images. This is referred to as air contrast. The purpose of this operation is to examine the large intestine; however, it can also be used to examine the last portion of the small intestine.
Computed Tomography (CT) Scan
A CT scan is a type of imaging procedure that employs x-rays to create comprehensive cross-sectional images of the body. A CT scan, unlike a typical x-ray, produces detailed images of the body's soft tissues.
If you experience abdominal (belly) pain, a CT scan may be used to determine the source of the problem. Although small intestinal cancers may not always be visible on a CT scan, these scans are useful in demonstrating some of the complications that these tumors can bring. CT scans can also be used to locate sites where cancer has spread.
- CT enteroclysis. This test can be utilized to get a better image of the intestine than a regular CT scan. A tiny tube is passed through the nose or mouth and into the small intestine before the scan. The tube is then filled with a large amount of liquid contrast material, which helps stretch the intestine and makes it easier to see on a CT scan.
- CT-guided needle biopsy. CT images can be used to accurately guide a biopsy needle into an unusual location where cancer may have progressed. You will remain on the CT scanning table for this procedure, which is called a CT-guided needle biopsy, while the doctor slides a biopsy needle through the skin and toward the mass. The CT scans are redone until the needle is completely inside the mass. After that, little samples of tissue are taken and examined.
Magnetic Resonance Imaging (MRI)
MRI scans, like CT scans, produce detailed images of the body's soft tissues. MRI scans, on the other hand, employ radio waves and strong magnets instead of x-rays.
Because MRI scans can reveal a lot of information in soft tissues, they can be useful in persons with suspected small intestine cancers. However, because a CT scan is often a simpler test to do, it is frequently used instead.
- MR enteroclysis. This test can be utilized to provide a better image of the intestine than a conventional MRI scan. A tiny tube is inserted down the nose or mouth and into the small intestine before the scan. The tube is then filled with a considerable amount of liquid contrast agent, which helps stretch the intestine and makes it easier to view on an MRI.
An endoscopy is a procedure in which a doctor inserts a flexible, lighted tube with a small video camera into the body to examine the GI tract's inner lining. Small pieces can be biopsied through the endoscope if abnormal regions are discovered.
- Upper endoscopy
The esophagus, stomach, and duodenum are examined using upper endoscopy. The endoscope is inserted into the mouth, followed by passage through the esophagus, stomach, and first part of the small intestine. Small samples of tissue can be extracted if the doctor notices any abnormalities and examined under a microscope to discover if cancer is present.
The majority of patients who are undergoing this test are given medication to make them asleep. If this is the case, you will very certainly require transportation home.
This test is useful for examining the small intestine's first segment. To examine the remainder of the small intestine, additional tests such as capsule endoscopy and double-balloon enteroscopy are required.
- Capsule endoscopy
An endoscope is not used in this procedure. Instead, you'll ingest a capsule with a light and a tiny camera. The capsule passes through the stomach and enters the small intestine just like any other tablet. It takes thousands of images as it goes through the small intestine. The images are sent from the camera to a gadget worn around the waist while going about everyday activities. The images can then be transferred to a computer and seen as a video by the doctor. During a normal bowel movement, the capsule goes out of the body and is flushed down the toilet.
- Double-balloon endoscopy
An upper endoscopy can't see most of the small intestine because it's too long and has too many curves. By utilizing a specific endoscope that is made up of two tubes, one inside the other, double-balloon enteroscopy avoids these issues.
You may be given intravenous medication or possibly a general anesthetic to help you relax. Depending on whether a specific region of the small intestine needs to be examined, the endoscope is introduced through the mouth or the anus.
The inner tube is pushed forward a short distance once within the small intestine, and then a balloon at the end is inflated to secure it. The outer tube is then pushed forward until it reaches the inner tube's end, where it is fixed in place with a balloon. This procedure is performed several times, allowing the doctor to examine the gut one foot at a time.
When used with capsule endoscopy, this test can be beneficial. The doctor can biopsy anything that seems abnormal, which is an advantage of this test over capsule endoscopy.
Because you will be given medication to keep you asleep for the procedure, you will need to be driven by someone you know.
Endoscopy and imaging studies can detect spots that appear to be cancerous, but a biopsy is the only method to tell for sure. A biopsy involves removing a bit of the abnormal area and examining it under a microscope.
There are several methods for obtaining biopsy samples from an intestinal tumor.
- During an endoscopy, a biopsy can be performed. When a tumor is discovered, the doctor can take small samples of the tumor with biopsy forceps through the tube. Despite the small size of the samples, doctors can typically make an accurate diagnosis. Bleeding following a biopsy is a rare but serious complication. If hemorrhage becomes a worry, doctors can use an endoscope to inject medications that constrict blood vessels into the tumor to stop the bleeding.
- In some cases, surgery is required to biopsy an intestinal tumor. If an endoscope cannot reach the tumor, this procedure may be used.
- CT scans or other imaging tests are sometimes used to guide a thin, hollow needle into other organs to biopsy tumors to assess if they are cancerous.
Small Intestine Cancer Treatment
Small Intestine Sarcoma
GIST and non-GIST tumors are both small intestinal sarcomas. The treatment of such lesions differed depending on the type that was discovered. Because activating mutations involving the KIT proto-oncogene have been discovered in GISTs, this pathway has been selected as a target for therapy. KIT inhibitors, particularly Imatinib, have become first-line therapy. Node resection is not suggested for such lesions since they seldom spread to regional lymph nodes, hence there is a distinct difference in care for GIST and non-GIST tumors. Surgical resection entails removing the original lesion with special attention paid to preventing intraoperative leakage of the resected tissue.
Small Intestine Adenocarcinoma
Wide segmental surgical resection is the most common treatment for localized small intestine cancer. When the tumor is surgically removed, the related mesentery is removed as well. Nodes are resected as part of the surgical resection since this helps decide whether or not adjuvant chemotherapy is required. A Whipple's surgery may be performed if the tumor is big and affects the first and second segments of the small bowel.
Small Intestine Neuroendocrine Tumors
The bulk of neuroendocrine tumors occur in the jejunum and ileum and are often easily distinguished. In most situations, they have been described as indolent. They do, however, have the ability to spread. As a result, excision of the tumor together with the neighboring mesentery and lymph nodes is usually indicated. This is true for those who have a limited condition. Curative surgery is unlikely to be an option for patients with advanced disease. As a result, surgical intervention is usually limited to debulking and palliative objectives.
Small Intestine Lymphoma
Non-Hodgkin lymphoma is the most common type of lymphoma found in the gastrointestinal tract. Surgical removal and adjuvant chemotherapy are used to treat the majority of small intestine lymphoma cases, depending on the histological subtype of NHL. Due to the numerous problems associated with radiation to the abdominal cavity, adjuvant radiotherapy is a less-desired alternative. Studies have shown that the advantages do not exceed the risks in the long run.
Small Intestine Cancer Prognosis
The 5-year survival rate for small intestinal cancer is 87 percent when discovered early. The 5-year survival rate for small bowel cancer that has progressed to neighboring tissues or organs, as well as regional lymph nodes, is 79 percent. The 5-year survival rate for cancer that has migrated to a distant portion of the body is 45 percent.
Small bowel cancer is a term used to describe a group of malignant tumors that can be seen throughout the small intestine, despite their rarity. Clinicians should be educated to make sure this is taken into account when ruling out causes of nonspecific gastrointestinal symptoms since this could lead to earlier diagnostic imaging and detection. Once the diagnosis has been established, patients should be educated on warning signs or symptoms of potential consequences. Supportive treatment should be offered by the palliative care team and support groups, according to the patient's prognosis based on the detected disease.