In short
Small intestine adenocarcinoma is a rare cancer that forms in the glandular cells lining the small intestine. Despite the small intestine making up 90% of the digestive tract, only 3 to 5% of digestive tract cancers occur there, making diagnosis challenging and often delayed.
What is Small Intestine Adenocarcinoma?
Small intestine adenocarcinoma is a type of cancer that starts in the glandular cells (cells that produce and release substances like mucus) that line the inside of the small intestine. It is the second most common type of cancer found in the small intestine, after neuroendocrine tumors.
This is a very rare cancer. Only about 11,000 Americans are diagnosed with small intestine cancer each year, accounting for fewer than 1% of all new cancer diagnoses. Small intestine adenocarcinoma represents about one-third of these cases.
Small intestine cancer is slightly more common among men than women, and it is typically diagnosed in people who are 65 and older.
Most adenocarcinomas occur in the duodenum, the first section of the small intestine that connects to the stomach. These tumors may grow and block the intestine as they develop. It is also possible for adenocarcinomas to form in other parts of the small intestine, including the jejunum (the middle section) or the ileum (the last and longest section).
In most cases, small intestine adenocarcinoma has already spread to other parts of the body when it is diagnosed.
Associated Anatomy
- Small intestine (duodenum, jejunum, ileum)
- Stomach
- Large intestine
The small intestine is part of the body's digestive system. It is a long tube that connects the stomach to the large intestine and folds many times to fit inside the abdomen. The digestive system removes and processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body.
What Causes This Cancer?
When certain cells within the small intestine mutate or change, they may begin to multiply uncontrollably, forming tumors or cancer. Cancer cells form because of genetic mutations, or changes in a cell's DNA, that cause it to multiply out of control. Researchers don't know exactly what causes these changes to occur.
One theory is that chronic inflammation within the small intestine has been linked with mutation and excessive cell reproduction. Over time, inflammation is believed to cause changes to cells within the small intestine, leading the cells to mutate and multiply uncontrollably.
Conditions like Crohn's disease, ulcerative colitis, celiac disease, and other digestive conditions may cause chronic inflammation of the small intestine. It may also be caused by smoking and alcohol consumption, as well as by certain dietary habits, such as eating a lot of red meat or saturated fat.
Signs and Symptoms
Many people don't have symptoms during the early stages of disease. Small intestine cancers are difficult to diagnose because the small intestine is not screened regularly, unlike the colon. People with small intestine cancer often don't notice symptoms until their disease has progressed. When symptoms do appear, they are often vague ones that could indicate many other problems related to the digestive system.
Those who do experience symptoms may have:
- Abdominal pain or cramping
- Unexplained weight loss
- Bleeding in the gastrointestinal tract, leading to blood in bowel movements (which may appear as fresh blood or dark-colored stool)
- Indigestion
- Bloating
- Nausea and/or vomiting
- Diarrhea
- A change in bowel habits
- Small bowel obstruction (blockage)
- Loss of appetite
- Weakness
- Jaundice (yellowing of the skin and the whites of the eyes)
- Anemia (low red blood cell count)
- Trouble breathing
- A lump in the abdomen
Risk Factors
A risk factor is anything that increases a person's chance of getting a disease. Not every person with one or more of these risk factors will develop small intestine cancer, and it will develop in some people who don't have any known risk factors.
Risk factors for small intestine adenocarcinoma include:
- Eating a high-fat diet
- Having Crohn's disease
- Having celiac disease
- Having familial adenomatous polyposis (FAP)
- Smoking and alcohol consumption
- Eating a lot of red meat or saturated fat
- Being 65 years old or older
- Being male
Diets high in red meat are associated with an increased risk of small bowel adenocarcinoma, whereas diets high in vegetables or dietary fiber have a protective effect.
How is it Diagnosed?
Small intestine cancers are difficult to diagnose. People suspected of having small bowel cancer often need multiple tests and procedures to locate the cancer or rule it out.
Procedures that make pictures of the small intestine and the area around it help diagnose small intestine cancer and show how far the cancer has spread. The process used to find out if cancer cells have spread within and around the small intestine is called staging. In order to plan treatment, it is important to know the type of small intestine cancer and whether the tumor can be removed by surgery.
Tests and procedures may include:
- Physical exam and health history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments is also taken.
- Blood tests: Blood tests can't detect small bowel cancer directly, but they can give clues about your health. A blood test called a complete blood count can detect a low red blood cell count. Blood tests also can show how well the organs are working.
- Imaging tests: Imaging tests create pictures of the body. They can show the location and size of small bowel cancer. Tests might include MRI (magnetic resonance imaging), CT scan (computed tomography), and PET scan (positron emission tomography).
- Upper endoscopy: A procedure to see inside the esophagus, stomach, and duodenum using a thin, lighted tube.
- Capsule endoscopy: A procedure where a patient swallows a small capsule containing a camera that takes pictures as it travels through the small intestine.
- Biopsy: A biopsy is a procedure to remove a sample of tissue for testing in a lab. The tissue might be removed during a procedure to see inside the small intestine. Sometimes surgery is needed to get the tissue sample. The sample is tested in a lab to see if it is cancer.
Treatment Options
Your healthcare team will create a treatment plan based on your health and specific information about the cancer. Surgery and chemotherapy are the main treatments for small intestine adenocarcinoma. Radiation therapy, targeted therapy, and immunotherapy are also treatment options for some people.
Surgery
Surgery is the main treatment for small intestine adenocarcinoma that can be completely removed. The type of surgery depends mainly on where the tumor is in the small intestine and if it can be completely removed.
Chemotherapy
Chemotherapy uses anticancer drugs to destroy cancer cells. It is sometimes used to treat small intestine adenocarcinoma, either after surgery or as the primary treatment for cancer that cannot be completely removed. The management of small intestine adenocarcinoma is largely extrapolated from colorectal cancer, which has had numerous advances over the past decade.
Recent studies have shown that the combination of capecitabine and oxaliplatin is highly active, with a median overall survival of 15 months in patients with metastatic disease.
Radiation Therapy
Radiation therapy uses high-energy rays or particles to destroy cancer cells. It is sometimes used to treat small intestine adenocarcinoma, particularly to shrink the cancer before surgery.
Targeted Therapy
Targeted therapy uses drugs that target specific features of cancer cells. In certain cases, targeted therapy may be offered for small intestine adenocarcinoma.
Immunotherapy
Immunotherapy is a treatment that helps your immune system fight cancer. It may be offered in certain cases of small intestine adenocarcinoma.
Outlook and Prognosis
Like colorectal cancer, when the cancer is localized at the time of diagnosis, the majority of patients will be cured. However, delays in diagnosis are frequent and the majority of patients will present with advanced-stage disease and either lymph node involvement or distant metastatic disease.
Small bowel adenocarcinoma is a rare malignancy of the gastrointestinal tract. However, these tumors are among those with worst prognosis due to vague clinical signs and symptoms and diagnostic challenges.
Your prognosis depends on numerous factors, including the cancer type, its stage, where the tumor started in your small intestine, and your overall health.
Follow-up Care
Follow-up care lets your healthcare team keep track of your health for a period of time after treatment ends. This important part of cancer care is often shared among the cancer specialists and your family doctor.
Small intestine adenocarcinoma often comes back (recurs). The chance of it recurring is greatest within 2 years, so you will need close follow-up during this time. Follow-up visits are usually scheduled every 3 months after the first treatment. If there are no signs of recurrence during this time, your doctor may schedule follow-up visits less often.
During follow-up visits, your healthcare team will usually ask questions about the side effects of treatment and how you're coping. Your doctor may do a physical exam and may have you undergo blood tests, imaging tests such as CT scans, and carcinoembryonic antigen (CEA) testing. If the CEA levels get higher over time, it could mean the cancer has come back.
Living with Small Intestine Adenocarcinoma
Supportive care helps people meet the physical, practical, emotional and spiritual challenges of cancer. It is an important part of cancer care. There are many programs and services available to help meet the needs and improve the quality of life of people living with cancer and their loved ones, especially after treatment has ended.
Nutrition and Short Bowel Syndrome
If the surgeon has to remove a large part of the small intestine to treat the cancer, there may not be enough tissue left for the small intestine to properly take in the nutrients and water from your food to keep you healthy. This is called short bowel syndrome.
The symptoms of short bowel syndrome include diarrhea, cramping, bloating, changes to the stool (pale, greasy and foul-smelling), heartburn, weakness and fatigue. Not getting enough nutrients can lead to weight loss, dehydration and malnutrition.
Your healthcare team might suggest medicines to treat diarrhea and heartburn. They may also suggest vitamin and mineral supplements, vitamin B12 injections, a high calorie diet, eating small meals often, or in some cases, tube feeding and parenteral nutrition (delivering liquid nutrients through a needle into your vein).
Fear of Recurrence
Small intestine adenocarcinoma often comes back after treatment, which can be very worrying. This is normal, but it's important to focus on living, taking care of your health and making the most of each day.
Living with Advanced Cancer
Many people with small intestine adenocarcinoma are diagnosed when the cancer is very advanced. A diagnosis of advanced cancer can be very hard to understand and accept.
Eating a healthy diet and exercising regularly are important parts of feeling your best after treatment ends.
