Pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors are complex tumors with unique characteristics that require specialized treatment. At Penn Medicine, our team focuses on these uncommon neuroendocrine tumors (NETs), giving you the best chance for effective care.

We have the experience to offer surgery when possible and further options when you need them. We prioritize the most pressing needs, protecting your health and quality of life while keeping an eye on your future.

What are pancreatic neuroendocrine tumors (islet cell tumors)?

Among the various types of neuroendocrine tumors, some develop in the pancreas, the organ providing digestive help and blood sugar control. These pancreatic neuroendocrine tumors — pancreatic NETs, or PNETs — are less common than NETs in the gastrointestinal tract.

Pancreatic NETs are not the same as pancreatic adenocarcinoma, which accounts for more than 90 percent of pancreatic cancers. Key differences include:

  • Cell types: Pancreatic NETs form in endocrine cells, which release hormones. These cells sit in clusters called islets, which is why pancreatic neuroendocrine tumors are also called islet cell tumors. Pancreatic adenocarcinoma develops in exocrine cells, which release digestive enzymes.
  • Symptoms: Pancreatic NETs and adenocarcinomas share some symptoms. But pancreatic NETs also cause their own signs of disease if their cells continue releasing hormones. About half of pancreatic neuroendocrine tumors behave this way.
  • Outlook: Pancreatic adenocarcinoma is usually a fast-moving disease. Pancreatic NETs grow slowly in most cases. So even though the disease has often metastasized (spread) by diagnosis, the prognosis for pancreatic NETs is typically more promising. The exception is a more unusual type called pancreatic neuroendocrine carcinoma (pancreatic NEC). These tumors grow and spread quickly.

Pancreatic neuroendocrine tumor types and symptoms

Sometimes symptoms of a pancreatic NET occur because the tumor has grown large or turned malignant (cancerous) and spread. These symptoms can overlap with other conditions, including more common forms of pancreatic cancer.

Signs and symptoms include:

  • Back or belly pain
  • Bone pain
  • Diarrhea
  • Indigestion
  • Jaundice (yellowing of skin or eyes)
  • Loss of appetite
  • Lump in the belly
  • Shortness of breath or coughing
  • Unintended weight loss

About half of pancreatic NETs release hormones that upset the body’s normal balance. This hormonal disruption may cause noticeable symptoms to show up while a tumor is still small.

The particular symptoms experienced depend on the form of tumor, named after the principal hormone released:

Risk factors for pancreatic neuroendocrine tumors and genetics

Doctors are often not sure why pancreatic neuroendocrine tumors form. Occasionally, a genetic mutation (also known as a variant) inherited from a parent leads to a pancreatic NET. Less than 10 percent of cases fall in this category. These variants are usually found in one of two genes:

  • MEN1: These variants lead to multiple endocrine neoplasia type 1, or MEN1. People with the condition are much more likely to develop a range of tumors. One possibility is gastrinoma or insulinoma, types of pancreatic NETs. People with MEN1 also have a higher risk for other NETs, including gastrointestinal neuroendocrine tumors and lung neuroendocrine tumors.
  • VHL: These variants cause Von Hippel-Lindau syndrome, associated with a variety of tumors. Fewer than one in five people with the condition develop a pancreatic NET, usually one that doesn’t release hormones. People with VHL may also develop another type of NET called pheochromocytoma.

Learn more about our genetic testing for neuroendocrine tumors, and our genetic counseling.

Diagnosing pancreatic neuroendocrine tumors

There are three main ways pancreatic NETs are discovered. Some people have symptoms from hormone release and see a doctor. Others experience symptoms of tumor growth or spread. Still, others undergo a scan for another medical reason and learn they might have a pancreatic growth.

Still, symptoms may not appear right away, especially if tumors don’t release hormones. When symptoms do occur, they can overlap with a range of conditions. Definitive answers can get delayed as a result. Most people age diagnosed between 30 and 60, and many have diseases that’s spread to the liver or elsewhere, like lymph nodes, bones and lungs.

Our thorough evaluation may include:

  • CT and MRI of the belly and pelvis
  • Endoscopy (examination with thin tubes with lights and cameras) of the GI tract, along with biopsy when needed
  • Needle biopsy if still needed, to analyze tumor cells to see if they are well-differentiated and how fast they’re dividing and multiplying
  • Blood tests to determine hormone levels
  • PET/CT imaging, either specially tailored for NETs or more general for aggressive cancers (learn more about nuclear medicine)

Pancreatic neuroendocrine tumor diagnosis

How we treat pancreatic neuroendocrine tumors

We create personalized treatment recommendations for you, based on a thorough review by our neuroendocrine tumor board. We consider:

  • Tumor size and rate of growth
  • Whether the tumor is releasing hormones and, if so, what kind
  • Whether cancer has spread and how extensively
  • If the liver is involved and how much disease it contains
  • Your symptoms
  • Your preferences and overall health

Treatment may involve watchful waiting, surgery to remove tumors or therapy for more extensive cancer:

Pancreatic neuroendocrine tumor treatment at Penn Medicine

Why choose Penn Medicine for a pancreatic NET?

With their distinct behaviors and characteristics, pancreatic NETs require an experienced team. Each member of our team is used to seeing these uncommon tumors. We care for a broad range of cases, for accurate diagnosis and effective treatment.

When you come to our program, you’ll find:

  • Expertise: Our doctors are recognized experts in their fields, with a deep understanding of pancreatic NET nuances. They help craft national treatment guidelines and participate in national working groups dedicated to research and improved care.
  • Collaboration: Doctors from a range of specialties meet at a weekly neuroendocrine tumor board to discuss cases. They identify individualized treatment recommendations, as well as the most effective timing and order of therapies — crucial for pancreatic NETs.
  • Options: Pancreatic NETs often need a variety of treatments spread over years. We offer a full range of options, from surgery and liver therapy to targeted therapy and nuclear medicine. We also develop new options. In fact, we ran the trial that led to the first nuclear medicine approval for pancreatic NETs.
  • Support: At our program, a nurse navigator helps with appointment scheduling and many other needs. We also provide GI symptom management for neuroendocrine tumors — diarrhea control is a frequent concern — and other ways to support neuroendocrine tumors.
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