What are Pancreatic Neuroendocrine Tumors? Symptoms, Causes, & Treatment

Pancreatic neuroendocrine tumors (PNETs) are rare growths that develop in the hormone-producing cells of your pancreas. Unlike the more common pancreatic cancer, these tumors often grow slowly and may be treatable, especially when caught early.

Your pancreas has two main jobs: making digestive enzymes and producing hormones like insulin. PNETs arise from the specialized cells that handle the hormone production side. While the word "tumor" can feel scary, many of these growths are manageable with proper medical care.

What are pancreatic neuroendocrine tumors?

Pancreatic neuroendocrine tumors are abnormal cell growths that form in your pancreas's hormone-making tissue. These tumors can either produce excess hormones themselves or remain "non-functioning," meaning they don't make extra hormones.

Think of your pancreas as having two different neighborhoods. Most people know about the part that helps digest food, but there's also a smaller area filled with hormone-producing cells called islet cells. PNETs develop specifically in this hormone-producing area.

The good news is that PNETs typically grow much slower than other types of pancreatic tumors. Many people live full, active lives after diagnosis and treatment. Some PNETs are even discovered accidentally during scans for other health issues.

What are the types of pancreatic neuroendocrine tumors?

PNETs fall into two main categories: functioning tumors that produce excess hormones, and non-functioning tumors that don't. The type you have determines which symptoms you might experience.

Functioning tumors make up about 30% of all PNETs and are named after the hormone they overproduce. The most common functioning PNETs include:

• Insulinomas: These produce too much insulin, causing dangerously low blood sugar levels
• Gastrinomas: These make excess gastrin, leading to severe stomach ulcers and acid production
• Glucagonomas: These create too much glucagon, causing high blood sugar and distinctive skin rashes
• VIPomas: These produce excess VIP hormone, causing severe, watery diarrhea
• Somatostatinomas: These are very rare and can cause diabetes-like symptoms

Non-functioning tumors make up about 70% of PNETs and don't produce excess hormones. They're often discovered when they grow large enough to press on nearby organs or during imaging tests for other reasons.

What are the symptoms of pancreatic neuroendocrine tumors?

Your symptoms depend largely on whether your tumor produces excess hormones or not. Non-functioning tumors may cause no symptoms at all in their early stages, while functioning tumors create specific problems based on which hormone they're overproducing.

If you have a non-functioning PNET, you might not notice anything until the tumor grows larger. When symptoms do appear, they often include:

• Abdominal pain or discomfort, especially in your upper belly
• Unexplained weight loss over several months
• Nausea or vomiting that doesn't seem related to other illness
• Yellowing of your skin or eyes (jaundice) if the tumor blocks bile ducts
• Changes in your bowel movements or stool color

Functioning tumors create symptoms related to hormone overproduction. If you have an insulinoma, you might experience episodes of shakiness, sweating, confusion, or rapid heartbeat when your blood sugar drops too low. These episodes often happen between meals or during physical activity.

Gastrinomas typically cause recurring stomach ulcers that don't respond well to standard treatments. You might have persistent stomach pain, heartburn, or nausea. Some people also develop chronic diarrhea.

Less common functioning tumors can cause distinctive symptoms. Glucagonomas may create a characteristic red, blistering rash on your legs, face, or abdomen, along with weight loss and mild diabetes. VIPomas cause profuse, watery diarrhea that can lead to dehydration and electrolyte imbalances.

What causes pancreatic neuroendocrine tumors?

The exact cause of most PNETs remains unknown, but researchers have identified several factors that may increase your risk. In most cases, these tumors develop sporadically without any clear trigger.

About 10% of PNETs are linked to inherited genetic conditions. The most common of these include:

• Multiple Endocrine Neoplasia Type 1 (MEN1): This syndrome increases your risk of tumors in multiple hormone-producing glands
• Von Hippel-Lindau disease: This condition can cause tumors in various organs, including the pancreas
• Neurofibromatosis Type 1: This genetic disorder may slightly increase PNET risk
• Tuberous sclerosis complex: This rare condition can occasionally involve pancreatic tumors

Having a family history of these genetic syndromes doesn't guarantee you'll develop a PNET, but it does mean regular monitoring might be helpful. Most people with PNETs have no family history of these conditions.

Researchers are still studying whether lifestyle factors like diet, smoking, or environmental exposures play a role in PNET development. Currently, there's no strong evidence linking these tumors to specific lifestyle choices.

When should you see a doctor for pancreatic neuroendocrine tumor symptoms?

You should contact your healthcare provider if you experience persistent symptoms that don't have an obvious explanation. While many symptoms can have benign causes, it's important to get them checked out, especially if they continue for several weeks.

Seek medical attention promptly if you notice recurring episodes of low blood sugar symptoms like shakiness, sweating, confusion, or rapid heartbeat, particularly if they happen between meals. These could indicate an insulinoma, which needs proper medical evaluation.

Schedule an appointment with your doctor if you develop persistent abdominal pain, unexplained weight loss, or recurring stomach ulcers that don't respond to standard treatment. While these symptoms can have many causes, they warrant professional evaluation.

Contact your healthcare provider immediately if you develop jaundice (yellowing of skin or eyes), severe abdominal pain, or profuse watery diarrhea that leads to dehydration. These symptoms may indicate that a tumor is affecting nearby organs or causing serious hormonal imbalances.

What are the risk factors for pancreatic neuroendocrine tumors?

Several factors may increase your likelihood of developing a PNET, though having risk factors doesn't mean you'll definitely develop this condition. Understanding these factors can help you and your doctor make informed decisions about monitoring and prevention.

The most significant risk factors you should be aware of include:

• Age: Most PNETs occur in people between 30 and 60 years old, though they can develop at any age
• Gender: These tumors affect men and women roughly equally, with slight variations depending on the specific type
• Genetic syndromes: Having MEN1, Von Hippel-Lindau disease, or related conditions significantly increases your risk
• Family history: A family history of pancreatic tumors or related genetic syndromes may increase your risk
• Race: Some ethnic groups may have slightly different risk patterns, though PNETs can affect people of all backgrounds

Unlike some other cancers, lifestyle factors like smoking, alcohol use, or diet don't appear to strongly influence PNET development. This means there aren't specific lifestyle changes that can definitively prevent these tumors.

If you have a known genetic syndrome that increases PNET risk, your doctor may recommend regular screening with imaging tests. This proactive approach can help catch any tumors early when they're most treatable.

What are the possible complications of pancreatic neuroendocrine tumors?

PNETs can cause complications both from the tumor itself and from the excess hormones some tumors produce. Understanding these potential issues can help you recognize when to seek medical attention and why treatment is important.

Physical complications from tumor growth may develop as the tumor enlarges. These can include:

• Obstruction of nearby organs, particularly the bile duct or small intestine
• Bleeding into the digestive tract if the tumor erodes blood vessels
• Spread to nearby lymph nodes or other organs in more advanced cases
• Pressure on surrounding pancreatic tissue, potentially affecting normal pancreas function

Hormonal complications occur specifically with functioning tumors and can be quite serious if left untreated. Insulinomas can cause severe hypoglycemia that may lead to seizures, coma, or brain damage if blood sugar drops critically low.

Gastrinomas can create Zollinger-Ellison syndrome, where excess stomach acid causes severe ulcers that may perforate or bleed. These ulcers often don't respond to standard ulcer treatments, making proper diagnosis crucial.

Rare functioning tumors can cause their own specific complications. VIPomas may lead to dangerous dehydration and electrolyte imbalances from excessive diarrhea. Glucagonomas can cause severe diabetes and nutritional deficiencies.

The good news is that most complications are preventable with proper treatment. Early diagnosis and appropriate management can help you avoid these serious issues while maintaining a good quality of life.

How are pancreatic neuroendocrine tumors diagnosed?

Diagnosing PNETs involves several steps, starting with your medical history and symptoms, followed by specific blood tests and imaging studies. Your doctor will work systematically to confirm the diagnosis and determine the tumor's characteristics.

Your healthcare provider will first ask about your symptoms, family history, and any genetic conditions that might increase your risk. They'll perform a physical exam, checking for signs like abdominal tenderness, enlarged organs, or jaundice.

Blood tests play a crucial role in PNET diagnosis. Your doctor may check for:

• Hormone levels like insulin, gastrin, or glucagon if a functioning tumor is suspected
• Chromogranin A, a protein often elevated in neuroendocrine tumors
• Standard blood chemistry to check liver function and overall health
• Genetic testing if you have a family history of related conditions

Imaging studies help locate and characterize the tumor. CT scans with contrast can show the tumor's size and location, while MRI provides detailed images of soft tissues. A specialized scan called an octreotide scan can specifically highlight neuroendocrine tumors.

Endoscopic ultrasound allows your doctor to get very detailed images of your pancreas and may include taking a small tissue sample (biopsy) for definitive diagnosis. This procedure uses a thin, flexible tube with an ultrasound probe passed through your mouth and stomach.

The biopsy provides the final confirmation of diagnosis and helps determine the tumor's grade, which indicates how quickly it's likely to grow. This information is crucial for planning your treatment.

What is the treatment for pancreatic neuroendocrine tumors?

Treatment for PNETs depends on several factors, including the tumor's size, location, whether it produces hormones, and whether it has spread. The good news is that many treatment options are available, and the outlook for PNETs is generally more positive than for other pancreatic tumors.

Surgery is often the first-line treatment when the tumor is localized and can be safely removed. Depending on the tumor's location, your surgeon might remove just the tumor itself, part of your pancreas, or in some cases, perform a more extensive procedure called a Whipple operation.

For functioning tumors, managing hormone-related symptoms is equally important as treating the tumor itself. Insulinomas may require medications to prevent dangerous drops in blood sugar, while gastrinomas often need proton pump inhibitors to reduce stomach acid production.

When surgery isn't possible or the tumor has spread, other treatment options include:

• Somatostatin analogs: Medications like octreotide that can slow tumor growth and control hormone production
• Targeted therapy: Drugs like everolimus or sunitinib that specifically target tumor growth pathways
• Chemotherapy: Used for more aggressive tumors or when other treatments aren't effective
• Peptide receptor radionuclide therapy (PRRT): A specialized treatment that delivers radiation directly to tumor cells
• Liver-directed therapy: Treatments specifically for tumors that have spread to the liver

Your treatment team will likely include several specialists working together, including gastroenterologists, oncologists, surgeons, and endocrinologists. This collaborative approach ensures you receive comprehensive care tailored to your specific situation.

How can you manage symptoms at home during treatment?

Managing PNET symptoms at home involves working closely with your healthcare team while taking practical steps to maintain your comfort and quality of life. Your specific home care needs will depend on whether your tumor produces excess hormones and what treatment you're receiving.

If you have an insulinoma, managing blood sugar levels becomes a daily priority. Keep quick-acting carbohydrates like glucose tablets, fruit juice, or crackers readily available to treat low blood sugar episodes. Eating small, frequent meals throughout the day can help prevent dangerous drops in blood sugar.

For gastrinomas causing excess stomach acid, taking prescribed acid-reducing medications consistently is crucial. Avoid foods that trigger your symptoms, such as spicy, acidic, or fatty foods. Eating smaller, more frequent meals can also help reduce acid production and improve comfort.

General symptom management strategies that may help include:

• Maintaining a symptom diary to track patterns and triggers
• Staying hydrated, especially if you experience diarrhea or vomiting
• Getting adequate rest and managing stress through relaxation techniques
• Following your prescribed medication schedule exactly as directed
• Maintaining regular contact with your healthcare team about symptom changes

Pain management may involve both prescribed medications and comfort measures like heat therapy or gentle exercise as approved by your doctor. Don't hesitate to contact your healthcare provider if your symptoms worsen or if you develop new concerns.

Nutritional support is often important, especially if you're experiencing weight loss or digestive symptoms. A registered dietitian familiar with PNETs can help you develop an eating plan that supports your health while managing any food-related symptoms.

How should you prepare for your doctor appointment?

Preparing thoroughly for your doctor appointment can help ensure you get the most from your visit and provide your healthcare team with the information they need to help you. Taking time to organize your thoughts and questions beforehand makes the appointment more productive for everyone.

Start by writing down all your symptoms, including when they started, how often they occur, and what makes them better or worse. Be specific about timing, such as whether symptoms happen before meals, after eating, or at particular times of day.

Gather important information to bring with you:

• A complete list of all medications, supplements, and vitamins you take
• Your family medical history, especially any cancers or genetic conditions
• Previous test results, scans, or medical records related to your current concerns
• Insurance cards and identification
• A trusted friend or family member for support and to help remember information

Prepare a list of questions you want to ask your doctor. Consider questions about your diagnosis, treatment options, potential side effects, and what to expect moving forward. Don't worry about asking too many questions – your healthcare team wants to make sure you understand your condition and treatment.

Think about your goals and concerns regarding treatment. Are you most worried about symptom control, long-term prognosis, or how treatment might affect your daily life? Sharing these priorities helps your doctor tailor their recommendations to what matters most to you.

Consider bringing a notebook or asking if you can record important parts of the conversation (with permission). Medical information can be overwhelming, and having a record helps you review and share information with family members later.

What's the key takeaway about pancreatic neuroendocrine tumors?

The most important thing to understand about PNETs is that they're generally more treatable and have a better outlook than other types of pancreatic tumors. While receiving any tumor diagnosis can feel overwhelming, many people with PNETs live full, active lives with proper medical care.

Early detection and appropriate treatment make a significant difference in outcomes. If you're experiencing persistent symptoms, especially those related to blood sugar fluctuations or recurring stomach issues, don't hesitate to seek medical evaluation. Many PNETs grow slowly, giving you and your healthcare team time to develop an effective treatment plan.

Remember that PNET treatment has advanced significantly in recent years, with new medications and techniques offering hope even for more advanced cases. Your healthcare team will work with you to find the treatment approach that best fits your specific situation and goals.

Living with a PNET often means building a strong relationship with your healthcare team and learning to manage your condition as part of your daily routine. With proper medical care, symptom management, and support from family and friends, you can maintain a good quality of life while managing your condition effectively.