Cancerwise

The duodenum is the first part of your small intestine, also known as your small bowel. It is connected to your stomach. It helps with digestion by absorbing nutrients and water from the foods you eat after they enter your stomach. 

Cancer that develops in the duodenum is known as duodenal cancer. You may sometimes hear it called “small intestine cancer” or “small bowel cancer.” But those actually describe all cancers that develop in the small intestine. Duodenal cancer is cancer that specifically develops in the duodenum.

Here, I’ll share more about duodenal cancer, including symptoms, treatment and why it can be hard to diagnose.

How rare is duodenal cancer?

The most common type of duodenal cancer is duodenal adenocarcinoma. This is a very rare type of cancer. Other types of cancer, such as neuroendocrine tumors, lymphomas or sarcomas, can also occur in the duodenum in rare cases.

To put it in perspective, small intestine cancers account for just 3% of all gastrointestinal cancer diagnoses in the U.S. About 4,000 to 5,000 of those diagnoses are small intestine adenocarcinomas, with over half of them being duodenal adenocarcinomas.

Some doctors may see only one or two of these diagnoses in their lifetime. But we see a lot of duodenal cancers at UT MD Anderson because we’re a specialized cancer center and we’ve done a lot of research in this space.

What causes duodenal cancer?

Doctors don’t know exactly what causes duodenal cancer. It’s most often diagnosed in older adults in their 60s.

There are factors that increase your risk for developing duodenal cancer. These risk factors include:

• Celiac disease: This is an autoimmune disorder in which digesting gluten causes damage to the lining of the small intestine.
• Lynch syndrome: This is a genetic condition that increases the chance of a person developing several cancers and developing them earlier than normal.
• Familial adenomatous polyposis (FAP): This inherited disorder is caused by a mutation in the APC gene. It leads to the development of hundreds to thousands of precancerous colon polyps throughout the gastrointestinal tract.
• Peutz-Jeghers syndrome: Caused by a mutation in the STK11 gene, this genetic disorder can cause polyps to form in your gastrointestinal tract. It increases your risk for several cancers. 

What are the symptoms of duodenal cancer?

Duodenal cancer and small intestine cancer typically have the same symptoms. The most common duodenal cancer symptoms include:

• Abdominal pain
• Bowel changes
• Nausea
• Weight loss
• Iron deficiency anemia
• Blockage in the gastrointestinal tract

These symptoms are similar to symptoms caused by other digestive issues. So, people often overlook duodenal cancer symptoms, which can allow the cancer to grow.

See your doctor if you have any of these symptoms, so they can determine the cause and provide treatment.

How is duodenal cancer diagnosed?

Diagnosing duodenal cancer can be challenging because the small intestine is not an easy area to evaluate. It’s about 20 feet long, and it wraps and curls.

Imaging tests like CT scans and MRIs can help your doctor see inside your small intestine. Your doctor may also perform an upper endoscopy to see inside your duodenum. This is when a scope is inserted into your mouth and passes down your digestive tract into your duodenum. During the procedure, your doctor may also get a tissue sample to biopsy.

At UT MD Anderson, we use a capsule endoscopy. This is a procedure in which you swallow a capsule that contains a camera. As it passes through your digestive tract, it takes pictures of your small intestine and sends them to a recorder on a belt that is placed around your waist.

Because symptoms of duodenal cancer are often non-specific, it’s often diagnosed at advanced stages. At times, symptoms may not appear until the tumor grows large enough to cause a blockage in the small intestine. Often, a person will then have surgery to remove the blockage, and a biopsy shows that they have adenocarcinoma.

Adenocarcinomas can develop in the pancreas, biliary duct, the ampulla of Vater and duodenum. It’s important to determine where exactly the cancer developed, so you get the correct treatment.

Your doctor will use their clinical expertise, imaging, pathology and molecular profile of the tumor to diagnose duodenal cancer.