Small intestine cancer is one of the rarest GI cancers globally, accounting for less than 1% of all cancer diagnoses worldwide. An estimated 64,477 cases were diagnosed globally in 2020, with North America bearing a disproportionately high burden.
Cases have more than doubled over the past 40 years in the developed world, driven by rising rates of obesity, physical inactivity, alcohol and tobacco use, and consumption of red and processed meats. Around 20% of cases are linked to hereditary or predisposing conditions.
The rising trend is comparable between men and women, but more pronounced in adults aged 50–74.
There are several distinct types of small intestine cancer, and the specific type drives the treatment plan. Neuroendocrine neoplasms (NET) and adenocarcinoma are the most common subtypes. Most cases are diagnosed at advanced stages due to few early symptoms and limited screening tools, making it aggressive and hard to treat when caught late.
The small intestine (also called small bowel) connects the stomach to the large intestine. The small bowel is actually the largest part of the GI tract and runs about 20 feet long. It helps break down food, absorb nutrients, and create waste. Most of the body’s absorption comes from the small bowel.
There are three main sections: the duodenum, which connects to the stomach; the jejunum which is in the middle; and ileum, which is the longest section and connects to the large intestine.
There are several types of cancers found in the small intestine because there are several types of cells in the small bowel.
Neuroendocrine tumors form in the neuroendocrine cells, which are responsible for hormones and releasing digestive juices. These tumors tend to be slow growing.
These are cancers that begin in glands that line internal organs and make mucus and other fluids. A third of small intestine cancers are adenocarcinomas, and they are most likely to form in the duodenum, near the stomach.
These are cancers that start in connective tissues (like cartilage or muscle) and most likely to occur near the ileum. The most common sarcomas are gastrointestinal stromal tumors (GISTs, also known as leiomyosarcoma.
These are cancers that begin in immune cells (white blood cells) called lymphocytes.
Staging helps you understand the size of your tumor, where the cancer is now, and the best treatment plan for your unique situation.
Staging small intestine cancer starts with identifying what type of cancer you have; adenocarcinomas are staged differently than NET, lymphoma, or sarcomas.
Adenocarcinomas are staged on a scale from 0-4 (many researchers use roman numerals 0-IV) using the TNM staging system. In general:
Risk factors put you at a higher risk of getting cancer. Some risk factors can be controlled with lifestyle changes, and others cannot. Older age, smoking, and obesity increase your risk of many cancers.
Just because you have a risk factor, that doesn’t mean you will get cancer.
These are scenarios researchers have found that can increase your risk:
There are not any formal, established screening guidelines for small intestine cancer. However, if you have an inherited syndrome or are at higher risk, doctors may recommend upper endoscopies, CT scans, or ultrasounds to monitor the small bowel and catch and remove any pre-cancerous polyps.
As with every cancer, there are steps you can take to adopt a healthy lifestyle and reduce your overall cancer risk, such as maintaining a healthy weight, not smoking, and limiting or eliminating alcohol.
Learn more about cancer prevention from the American Institute for Cancer Research.
According to Gastroenterology (2023)
According to research in MPDI:
Small bowel cancer is highly treatable if caught early. Doctors use what’s called “survival statistics” to understand the likelihood of a patient beating the disease.
Survival varies significantly by subtype: neuroendocrine tumors have a 5-year survival of around 85%, while small bowel adenocarcinoma (the most aggressive form) has a 5-year survival of 14-35%.
According to the National Cancer Institute, 71% of patients are alive five years after a small intestine cancer diagnosis.
Detailed survival statistics are based on where the cancer is located and if it has spread:
The cancer hasn’t spread
The cancer spread to nearby lymph nodes
The cancer has spread to lymph nodes and/or organs
Small intestine cancer can be challenging to find, especially because there’s several types of cancer within the one organ. Diagnosis delay is a significant problem for small intestine cancer. Small-bowel-specific imaging if symptoms persist without explanation.
These tests may be utilized to find and confirm cancer:
Ask your doctor about these additional tests—ideally before you begin treatment.
If you’re facing a diagnosis, the GI Cancers Alliance is here for you.
If you’re newly diagnosed, work with your doctor to create a treatment plan.
Small intestine cancer treatment plans may include:
We strongly encourage you to get a second opinion from another trusted doctor so you feel confident moving forward.
